Conduit sensor device propulsion apparatus and process for operating the propulsion apparatus

ABSTRACT

A conduit sensor device comprises a first end portion, a second end portion, a first magnet rotor assembly residing proximate the first end portion of the device and rotatable between first and second positions, a second magnet rotor assembly residing proximate the second end portion of the device and rotatable between first and second positions. The first magnet rotor assembly includes a first plurality of magnets axially arranged about a first axis. The first magnet rotor assembly includes a first top portion and a first bottom portion securing the first plurality of magnets within the first magnet rotor assembly. The second magnet rotor assembly includes a second plurality of magnets axially arranged about a second axis. The second magnet rotor assembly includes a second top portion and a second bottom portion securing the second plurality of magnets within the second magnet rotor assembly.

U.S. patent application Ser. No. 12/836,230 filed Jul. 14, 2010 ishereby incorporated by reference herein in its entirety by referencehereto the same as if written herein verbatim.

FIELD OF THE INVENTION

The invention is in the field of pipeline inspection devices/sensors.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 6,762,602 to Laursen et al. proposed a “device, e.g. aninspection pig, for inspecting conduits made from ferromagneticmaterials, such as pipelines, for faults, cracks, corrosion or the like,comprising at least one pulling element, a supporting structure ofvariable circumference, disposed on the pulling element and comprisingsubstantially radially disposed supporting arms each of which ispivotable about axes disposed perpendicular to the longitudinal centralaxis of the pulling element, and several permanent magnets disposed atthe circumference of the supporting structure for generating a magneticfiled, and with sensors.” Further, Laursen, states, pertinent part:“[f]or strengthening or weakening the magnetic field generated by thepermanent magnet in dependence on the circumference of the supportingstructure or in dependence on the lateral separation between thepermanent magnets. The permanent magnets are associated with furthermagnets having a magnetic field which can be varied in direction orstrength. In an embodiment, the further magnets associated with thepermanent magnets are permanent magnets, wherein the direction of theirmagnetic field can be changed by turning using an electric or mechanicalactuator. In another embodiment coils are used as magnets, which can besupplied with a variable current.” See, the Abstract of U.S. Pat. No.6,762,602 to Laursen et al.

The diametrical size of the conduit, the thickness of the conduit, andthe lateral separation of the poles of the magnet are factors in theperformance of the sensor. Sensors such as piezo-electric,electroacoustic, and electromagnetic sensors such as Hall, stray fieldand eddy current sensors may be used.

U.S. Pat. No. 6,762,602 to Laursen et al. does not effectively shunt themagnetic field produced by the poles through use of respective rotatablemagnets. Additionally, the drive system of the rotatable magnetsdisclosed in U.S. Pat. No. 6,762,602 to Laursen et al. involves amechanical system using springs and a toothed wheel with a selecteddiameter and selected number of teeth. The diameter and the number ofteeth may be changed to control the rotatable magnet. Further, a springis necessary for each of the rotatable magnets and adjustment of thosemagnets in a coordinated manner is difficult, and, therefore, control ofthe magnetic field is difficult. One of the poles in the Laursen '602patent may be adjusted differently than the other pole because thesprings and toothed gears cannot be matched or properly controlled.Spring constants and biasing of the rotatable magnets in Laursen et al.may not be equal and, hence, contribution of each of the poles to themagnetic field may be different.

Alternatively, U.S. Pat. No. 6,762,602 to Laursen et al., furtherdiscloses an electrically driven toothed wheel which is controlled byappropriate electric, electronic or mechanical sensor element fordetermining the lateral separation between the parallelogram supports.However, there is no disclosure in Laursen as to the coordinatedoperation and control of the rotatable magnets.

A more effective magnetic shunt which substantially completely reducesthe magnetic field associated with a plurality of inner peripheralsensors is needed for unpiggable pipe lines. So-called unpiggable pipelines require substantial cancellation of the magnetic field caused bypermanent magnets used in conduit sensors placed in proximity to theconduit/pipe line. When the field created by the permanent magnets issubstantially cancelled, the sensor may be drawn more easily through thepipeline as the sensor and its supporting structure are no longermagnetically attracted to the walls of the conduit/pipeline.

Use of a conduit sensor device requires application of north and southpoles in proximity to the conduit/pipe line wall which creates amagnetic field extending into the wall of the conduit/pipe line. Controlof the magnetic field which enters the conduit/pipe line is necessaryfor the correct interpretation of data obtained from the sensors.Sensors, such as a Hall effect sensors, measure anomalies such as cracksand deterioration of the structure of the conduit/pipeline when amagnetic field is imparted in the conduit/pipeline. Control of themagnetic field imparted in the conduit/pipeline is important as itallows correct interpretation of the data generated from the sensors. Assuch, a conduit sensor device which accurately controls the magneticfield in the conduit/pipeline wall is needed.

SUMMARY OF THE INVENTION

The conduit sensor disclosed herein controls the magnetic field asrequired to obtain accurate data and to allow movement through apipeline or conduit. Additionally, the conduit sensor disclosed hereinis self-propelled in two directions, forwardly and rearwardly.

There is a plurality of conduit sensor devices arranged on the innerperiphery of the pipeline/conduit which form an inspection pig. Eachconduit sensor device includes several sensors associated therewith andeach device covers a sector of the pipeline/conduit. Any number ofconduit sensors may be used to form an inspection pig.

Each conduit sensor device includes a magnetic shunt device. Themagnetic shunt device is used to effectively turn off the magneticfield. The inspection pig is propelled through the pipeline/conduit bydrive means which are disclosed herein. Each of the conduit sensordevices propels the conduit sensor device through the pipeline to beinspected. Further, and importantly, the magnetic shunt device enablesthe curtailment of the magnetic field in the pipeline/conduit makingmovement of the inspection pig within the interior of thepipeline/conduit and through valves and other obstructions inside thepipeline easier.

Further, the magnetic shunt device imparts an appropriately adjustablemagnetic field into the pipeline/conduit as dictated by the operation ofthe inspection pig and/or as required for other reasons such ascomparison of the data presently being taken against previously takendata for a given conduit/pipeline.

A conduit sensor device comprising a first end portion and a second endportion is disclosed. A first magnet rotor assembly resides proximatethe first end portion of the device and is rotatable between first andsecond positions. A second magnet rotor assembly resides proximate thesecond end portion of the device and is rotatable between first andsecond positions. The first position of the first magnet rotor assemblyin combination with the first position of the second magnet rotorassembly creates the maximum strength magnetic field. The secondposition of the second magnet rotor assembly in combination with thesecond position of the second magnet rotor assembly effectivelycompletely shunts the magnetic field rendering no magnetic field. Thefirst magnetic rotor assembly and the second magnetic rotor assemblymove in unison under the control of a shunt motor. In other words if theorientation of the first magnet rotor assembly is rotated 45° then theorientation of the second magnet rotor assembly is rotated 45° in thesame direction when viewed from the first end of the device. Preferably,a first and third rotor assembly reside proximate the first end of theconduit sensor device and a second and fourth rotor assembly resideproximate the second end of the conduit sensor device. The first andthird rotor assemblies proximate the first end are rotated 90° such thatthe top portions thereof face each other at the conclusion of the 90°rotation canceling the magnetic field when the shunt shaft is rotatedcounter clockwise with respect to the first end. Similarly, the secondand fourth rotor assemblies proximate the second end are rotated 90°such that the top portions thereof face away from each other at theconclusion of the 90° rotation canceling the magnetic field when theshunt shaft is rotated counter clockwise with respect to the first end.

The first magnet rotor assembly includes a first plurality of magnetsaxially arranged about a first axis, the first magnet rotor assemblyincludes a first top portion and a first bottom portion, and, the firsttop and bottom portions secure the first plurality of magnets within thefirst magnet rotor assembly. The second magnet rotor assembly includes asecond plurality of magnets axially arranged about a second axis, thesecond magnet rotor assembly includes a second top portion and a secondbottom portion, and, the second top and bottom portions secure thesecond plurality of magnets within the second magnet rotor assembly.

The first position of the first magnet rotor assembly orients the northpole of each of the first plurality of magnets radially outwardly. Thefirst position of the second magnet rotor assembly orients the southpole of each of the second plurality of magnets radially outwardly. Thesecond position of the first magnet rotor assembly orients the northpole of each of the first plurality of magnets at an angle of 90° withrespect to the first position; and, the second position of the secondmagnet rotor assembly orients the north pole of each of the secondplurality of magnets at an angle of 90° with respect to said firstposition. The direction of rotation depends on the direction of rotationof the shunt shaft with respect to the first end.

A worm drive is a gear arrangement in which a worm meshes with a wormwheel sometimes referred to as a worm gear. The terms “worm wheel” and“worm gear” are synonymous. The worm drives the worm wheel. The wormwheel is similar in appearance to a spur gear. A worm is essentially agear in the form of a screw.

The conduit sensor device includes a first drive mechanism for rotatingthe first magnet rotor assembly from the first position to the secondposition and a second drive mechanism for rotating the second magnetrotor assembly from the first position to the second position. The firstdrive mechanism includes a first vertical shunt worm for rotating thefirst magnet rotor assembly. The second drive mechanism includes asecond vertical shunt worm for rotating the second magnet rotorassembly. A shunt shaft extends between the first end portion of thedevice to the second end portion of the device. A first shunt shaft wormand a second shunt shaft worm are affixed to the shunt shaft. A firstshunt worm wheel engages the first shunt shaft worm and a second shuntworm wheel engages the second shunt shaft worm. The first shunt wormwheel is engaged with the first vertical shunt worm wheel and isrotatable therewith. The second shunt worm wheel is engaged with thesecond vertical shunt worm wheel and is rotatable therewith.

A first helical gear is affixed to the first magnet rotor assembly. Asecond helical gear is affixed to the second magnet rotor assembly. Thefirst helical gear is engaged with the first vertical shunt worm wheeland the second helical gear is engaged with the second vertical shuntworm wheel. The first magnet rotor assembly is rotatable with the firsthelical gear; and, the second magnet rotor assembly is rotatable withthe second helical gear.

A third magnet rotor assembly residing proximate the first end portionof the device and rotatable between first and second positions ispreferably used. A fourth magnet rotor assembly resides proximate thesecond end portion of the device and is rotatable between first andsecond positions is preferably used. The third magnet rotor assemblyincludes a third plurality of magnets axially arranged about a thirdaxis. The third magnet rotor assembly includes a third top portion and athird bottom portion. The third top and bottom portions secure the thirdplurality of magnets within the third magnet rotor assembly. The fourthmagnet rotor assembly includes a fourth plurality of magnets axiallyarranged about a fourth axis. The fourth magnet rotor assembly includesa fourth top portion and a fourth bottom portion. The fourth top andbottom portions secure the fourth plurality of magnets within the fourthmagnet rotor assembly.

The first position of the third magnet rotor assembly orients the northpole of each of the third plurality of magnets radially outwardly. Thefirst position of the fourth magnet rotor assembly orients the southpole of each of the fourth plurality of magnets radially outwardly. Thesecond position of the third magnet rotor assembly orients the northpole of each of the third plurality of magnets at an angle of 90° withrespect to the first position. The second position of the fourth magnetrotor assembly orients the north pole of each of the fourth plurality ofmagnets at an angle of 90° with respect to said first position. Thedirection of rotation of the first and third magnet rotor assembliesdepends on the direction of rotation of the shunt shaft.

A third drive mechanism rotates the third magnet rotor assembly from thefirst position to the second position and a fourth drive mechanismrotates the fourth magnet rotor assembly from the first position to thesecond position. The third drive mechanism includes the first verticalshunt worm for rotating the third magnet rotor assembly; and, the fourthdrive mechanism includes the second vertical shunt worm for rotating thefourth magnet rotor assembly.

A third helical gear is affixed to the third magnet rotor assembly. Thefourth helical gear is affixed to the fourth magnet rotor assembly. Thethird helical gear is engaged with the first vertical shunt worm. Thefourth helical gear is engaged with the second vertical shunt worm. Thethird magnet rotor assembly is rotatable with the third helical gear;and, the fourth magnet rotor assembly is rotatable with the fourthhelical gear.

Another example of the conduit sensor device is disclosed which includesa first end of the device and a second end of the device. A first magnetrotor assembly, a third magnet rotor assembly, a third magnet rotorassembly, and a fourth magnet rotor assembly are disclosed. The firstmagnet rotor assembly and the second magnet rotor assembly reside at thefirst end of the device. The second magnet rotor assembly and the fourthmagnet rotor assembly reside at the second end of the device. The firstand third magnet rotor assemblies are rotationally movable in a range ofpositions between a first position and a second position at the firstend of the device. The third and fourth magnet rotor assemblies arerotationally movable in a range of positions between a first positionand a second position at the second end of the device. A magnetic shuntshaft includes first and second ends, the first end of the magneticshunt shaft resides at the first end of the device and the second end ofthe magnetic shunt shaft resides at the second end of the device. Afirst gearbox resides at the first end of the device and a secondgearbox resides at the second end of the device. A first worm is affixedto the first end of the magnetic shunt shaft and a second worm isaffixed to the second end of the magnetic shunt shaft. The first gearboxincludes: a first wheel worm; a first vertical worm affixed to the firstwheel worm; a first helical gear, the first helical gear engages thefirst vertical worm; and, a third helical gear, the third helical gearengages the first vertical worm gear. The first magnet rotor assembly isaffixed to the first helical gear and is rotatable therewith. The thirdmagnet rotor assembly is affixed to the third helical gear and isrotatable therewith. The first worm is affixed to the first end of themagnetic shunt shaft and engages the first wheel worm and drives thefirst vertical worm affixed to the first wheel worm. The first verticalworm drives the first helical gear and the first magnet rotor assemblyin a first rotational direction between first and second positions andthe first vertical worm drives the third helical gear and the thirdmagnet rotor assembly in a second rotational direction opposite to thefirst rotational direction of the first helical gear between first andsecond positions. The second gearbox includes: a second wheel worm; asecond vertical worm affixed to the second wheel worm; a second helicalgear, the second helical gear engages the second vertical worm; and, afourth helical gear, the fourth helical gear engages the second verticalworm. The second magnet rotor assembly is affixed to the second helicalgear and is rotatable therewith. The fourth magnet rotor assembly isaffixed to the third helical gear and is rotatable therewith. The secondworm affixed to the second end of the magnetic shunt shaft engages thesecond wheel worm and drives the second vertical worm affixed to thesecond wheel worm. The second vertical worm drives the second helicalgear and the second magnet rotor assembly in a first rotationaldirection between the first and second positions and the second verticalworm drives the fourth helical gear and the fourth magnet rotor assemblyin a second rotational direction opposite to the first rotationaldirection of the second helical gear between the first and secondpositions. When the first and third magnet rotor assemblies are in thefirst position and when the second and fourth magnet rotor assembliesare in the first position, a magnetic field of maximum strength isgenerated between the first and the second magnet rotor assemblies andthe third and fourth magnetic rotor assemblies, and, the magnetic fieldof maximum strength extends into a conduit. When the first and thirdmagnet rotor assemblies are in the second position and when the secondand fourth magnet rotor assemblies are in the second position, nomagnetic field exists between the first and second magnet rotorassemblies and no magnetic field exists between the third and fourthmagnet rotor assemblies. When the first and second magnet rotorassemblies are in a rotational position intermediate the first andsecond positions, and when the third and fourth magnet rotor assembliesare in a rotational position intermediate the first and secondpositions, then the strength of the magnetic field between the first andsecond magnet rotor assemblies is modified according to the rotationalpositions of said first and second magnet rotor assemblies, and then thestrength of the magnetic field between the third and fourth magnet rotorassemblies is modified according to the rotational positions of thesecond and fourth magnet rotor assemblies.

The first magnet rotor assembly includes a plurality of magnets and eachone of the plurality of magnets includes a north pole and a south pole.The second magnet rotor assembly includes a plurality of magnets andeach one of the plurality of magnets includes a north pole and a southpole. The third magnet rotor assembly includes a plurality of magnetsand each one of the plurality of magnets includes a north pole and asouth pole. The fourth magnet rotor assembly includes a plurality ofmagnets and each one of the plurality of magnets includes a north poleand a south pole. When the first and third magnet rotor assemblies arein the first position: the south poles of each of the plurality ofmagnets of the first magnet rotor assembly face downwardly away from theconduit and the north poles of each of the plurality of magnets of thefirst magnet rotor assembly face upwardly toward the conduit; and, thesouth poles of each of the plurality of magnets of the third magnetrotor assembly face downwardly away from the conduit and the north polesof each of the plurality of magnets of the third magnet rotor assemblyface upwardly toward the conduit. When the second and fourth magnetrotor assemblies are in the first position: the south poles of each ofthe plurality of magnets of the second magnet rotor assembly faceupwardly toward the conduit and the north poles of each of the pluralityof magnets of the second magnet rotor assembly face downwardly away fromthe conduit; and, the south poles of each of the plurality of magnets ofthe fourth magnet rotor assembly face upwardly toward the conduit andthe north poles of each of the plurality of magnets of the fourth magnetrotor assembly face downwardly away from the conduit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a plurality of conduit sensordevices, and, each of the conduit sensor devices includes a plurality ofsensors and magnetic shunts.

FIG. 2 is an enlargement of a portion of FIG. 1 illustrating the tubularradial control mechanism and a conduit sensor with magnetic shunt.

FIG. 3 is a schematic perspective view of one conduit sensor device withmagnetic shunt.

FIG. 3A is a schematic top view of the conduit sensor device withmagnetic shunt.

FIG. 3B is a schematic side view of the conduit sensor device withmagnetic shunt.

FIG. 3C is a schematic first end view of conduit sensor device withmagnetic shunt.

FIG. 3D is a schematic second end view of conduit sensor device withmagnetic shunt.

FIG. 3E is a schematic perspective view of the second backing barweldment of the conduit sensor device with magnetic shunt.

FIG. 3F is another schematic perspective view of the second backing barweldment of the conduit sensor device with magnetic shunt.

FIG. 3G is a schematic end view of the second backing bar weldment ofthe conduit sensor device with magnetic shunt.

FIG. 3H is a schematic perspective view of the second half of the gearbox of the first end of the conduit sensor device with magnetic shunt.

FIG. 3I is another schematic perspective view of the second half of thegear box of the first end of the conduit sensor device with magneticshunt.

FIG. 3J is a schematic perspective view of the first half of the gearbox of the first end of the conduit sensor device with magnetic shunt.

FIG. 3K is a schematic perspective view of the first half of the gearbox of the first end of the conduit sensor device with magnetic shunt.

FIG. 3L is a schematic plan view of the wheel propulsion drive shaft ofthe first end together with the drive gear.

FIG. 3M is a schematic plan view of the wheel propulsion drive shaft ofthe first end.

FIG. 3N is a schematic perspective view of the bottom plate of the firstend of conduit sensor device with magnetic shunt.

FIG. 3O is another schematic perspective view of the bottom plate of thefirst end of conduit sensor device with magnetic shunt.

FIG. 4 is cross-sectional schematic view taken along the line 4-4 ofFIG. 3A.

FIG. 4A is a cross-sectional schematic view taken along the line 4-4 ofFIG. 3A.

FIG. 5 is a cross-sectional schematic view taken along the lines 5-5 ofFIG. 3A.

FIG. 5A is a cross-sectional schematic view taken along the lines 5-5 ofFIG. 3A with a pipe in the view.

FIG. 5B is a cross-sectional schematic view taken along the lines 5-5 ofFIG. 3A with rotor assemblies rotated 90°.

FIG. 6 is a cross-sectional schematic view taken along the line 6-6 ofFIG. 3A.

FIG. 6A is an enlargement of a portion of FIG. 6.

FIG. 6B is an enlargement of a portion of FIG. 6.

FIG. 7 is a schematic plan view of the magnet drive shaft, first endworm, spur gear affixed to shaft and second end worm.

FIG. 7A is a cross-sectional view taken along the lines 7A-7A of FIG. 7.

FIG. 7B is an enlargement of the first end portion of FIG. 7.

FIG. 7C is a cross-sectional enlargement of the first end portion ofFIG. 7.

FIG. 7D is an enlargement of the second end portion of FIG. 7.

FIG. 7E is a cross-sectional enlargement of the second end portion ofFIG. 7.

FIG. 7F is a top view of partial cylinder which provides thrust bearingsupport for the magnet drive shaft.

FIG. 7G is an end view of the partial cylinder which provides thrustbearing support for the magnet drive shaft.

FIG. 8 is a schematic plan view of magnet drive shaft, first end worm,spur gear affixed to shaft and second end worm.

FIG. 8A is a cross-sectional view taken along the lines 8A-8A of FIG. 8.

FIG. 8B is an enlargement of the first end portion of FIG. 8.

FIG. 8C is a cross-sectional enlargement of the first end portion ofFIG. 8.

FIG. 8D is an enlargement of the second end portion of FIG. 8.

FIG. 8E is a cross-sectional enlargement of the second end portion ofFIG. 8.

FIG. 9 is a schematic top view of the conduit sensor with magnetic shuntwith the backing bar weldments and the gear boxes removed illustratingthe first magnet rotor assembly, second magnet rotor assembly, thirdmagnet rotor assembly and fourth magnet rotor assembly.

FIG. 9A is a schematic bottom view of the first end of FIG. 9.

FIG. 9B is a schematic bottom view of the second end of FIG. 9.

FIG. 9C is a schematic perspective view of the first end of FIG. 9illustrating the first and third magnet rotor assemblies and associatedshunt gearing as well as the propulsion system gearing.

FIG. 9D is a schematic perspective view of the second end of FIG. 9illustrating the second and fourth magnet rotor assemblies andassociated gearing as well as the propulsion system gearing.

FIG. 9E is an exploded perspective view of one of the fourth magnetrotor assembly of the second end.

FIG. 9F is an exploded perspective view of the second and fourth magnetrotor assemblies of the second end.

FIG. 9G is a schematic perspective view similar to FIG. 9C indicatingrotation of the shunt drive shaft in the clockwise direction as definedfrom the perspective of the first end of the conduit sensor device andalso indicating rotation of the propulsion drive shaft in the clockwisedirection as defined from the perspective of the first end of theconduit sensor device.

FIG. 9H is a schematic perspective view similar to FIG. 9C indicatingrotation of the shunt drive shaft in the counter clockwise direction asdefined from the perspective of the first end of the conduit sensordevice and also indicating rotation of the propulsion drive shaft in thecounter clockwise directions as defined from the perspective of thefirst end of the conduit sensor device.

FIG. 9I is a schematic perspective view similar to FIG. 9D indicatingrotation of the shunt drive shaft in the clockwise direction as definedfrom the perspective of the first end of the conduit sensor device andalso indicating rotation of the propulsion drive shaft in the clockwisedirections as defined from the perspective of the first end of theconduit sensor device.

FIG. 9J is a schematic perspective view similar to FIG. 9D indicatingrotation of the shunt drive shaft in the counter clockwise direction asdefined from the perspective of the first end of the conduit sensordevice and also indicating rotation of the propulsion drive shaft in thecounter clockwise directions as defined from the perspective of thefirst end of the conduit sensor device.

FIG. 10 is a schematic cross-sectional view taken along the lines 10-10of FIG. 3.

FIG. 10A is a schematic cross-sectional view taken along the lines 10-10of FIG. 3 with the rotor assemblies of the second end rotated 90°.

FIG. 11 is a schematic cross-sectional view taken along the lines 11-11of FIG. 3.

FIG. 11A is a schematic cross-sectional view taken along the lines 11-11of FIG. 3 with the rotor assemblies of the first end rotated 90°.

DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic perspective view 100 of a plurality of conduitsensor devices 101, and, each of the conduit sensor devices 101 includesa plurality of sensors 106 and magnetic shunts. Arrow 101 is illustratedpointing to one conduit sensor with a magnetic shunt therein. Referencenumeral 102 is used to denote couplings between the plurality of conduitsensors and battery powered drive units 109. A tubular radial controlmechanism 103 controls wires/rods for extending the conduit sensors 101radially outwardly and for contracting the conduit sensors radiallyinwardly. Arrow 104 indicates the second end of one conduit sensor witha magnetic shunt and arrow 105 indicates the first end of one conduitsensor with magnetic shunt. Arrow 106 indicates electronic sensors usedto detect anomalies and defects in pipes and conduits. Referencenumerals 107, 107A, 108, 108A denote rubber/synthetic propulsion wheels.

FIG. 2 is an enlargement 200 of a portion of FIG. 1 illustrating thetubular radial control mechanism 103 and a conduit sensor 101 withmagnetic shunt. Also indicated is a spring 201 which is attached to thebottom of one of the conduit sensor devices 101. Each of the conduitsensor devices 101 has two springs 201 affixed thereto. These springsprovide the force to open the assembly as shown in FIG. 2 when theradial control mechanism 103 commands the radial movement of the conduitsensor devices 101. Wires/rods 103A, 103B support one conduit sensordevice 101 from the tubular radial control mechanism 103.

FIG. 3 is a schematic perspective view 300 of the conduit sensor device101 with magnetic shunt. Omitted from the drawings are numerous boltholes some of which are threaded and some of which are simplypassageways for the bolts. Also omitted from the drawings are numerousbolts which reside in the passageways and which interconnect the partsof the invention. In the central portion of the device, the firstbacking-bar weldment 301 and the second backing-bar weldment 302 areshown. First center roller, 303, and second center roller, 304, areillustrated in FIG. 3. Center rollers 303, 304 protect the conduitsensor device, and, more particularly, the sensors 106 from beingdamaged in the event that the device 101 is moved radially outwardlywith too much force. Center rollers 303, 304 include pins (unnumbered)which are affixed in apertures such as aperture 321 illustrated in FIG.3E. A recess 322 in the second backing bar weldment accommodates centerroller 303. Flat surface 323 of second backing bar weldment 302 is thearea in which the sensors 106 reside.

FIG. 3E is a schematic perspective view 300E of the second backing barweldment 302 of the conduit sensor with magnetic shunt. The magneticshunt is not illustrated in FIG. 3E. Referring to FIG. 3E, flat interiorface 320 of the second backing bar weldment 302 is illustrated. Thefirst magnet rotor assembly 991 resides in housing 326 in the secondbacking-bar weldment. Slot 324 resides in face 320 and provides room forsensor wiring. First magnet rotor assembly 991 resides substantially atthe first end of the device. Housing 326 is shown as a cylindricalaperture in the second backing bar weldment 302 in FIG. 3E. Arrow 327 isillustrated in FIG. 3E as pointing to another housing for second magnetrotor assembly 993. Second magnet rotor assembly 993 residessubstantially at the second end of the device. Still referring to FIG.3E, recess 329 provides space for the propulsion motor 620A asillustrated in FIG. 6. Recess 330 provides space for the shunt motor 698as illustrated in FIG. 6. FIG. 6 is a schematic cross-sectional view 600taken along the line 6-6 of FIG. 3A.

Referring to FIG. 3F, passageway 331 extends from the first end of thesecond backing bar weldment to the second end thereof and housespropulsion shaft 550 therein. First backing bar weldment 301 isreciprocally shaped with respect to second backing bar weldment 302. Inother words, the first backing bar weldment 301 includes reciprocallyshaped passageways and reciprocally shaped features described inconnection with the second backing bar weldment 302. For instance,backing bar weldment 301 includes a flat interior face which abuts theflat interior face 320 of the second backing bar weldment 302.Similarly, the first backing bar weldment 301 includes a recess which isthe reciprocal of recess 324 which allows room for wiring when mountedflushly with respect to the second backing bar weldment 302 and affixedto the second backing bar weldment 302. First backing bar weldment 301includes a passageway for housing magnet drive shaft 401 and thepassageway is reciprocal to passageway 331 (which houses propulsionshaft 550) and dimensionally the same as passageway 331. Further, thefirst backing bar weldment 301 includes reciprocally shaped recessescorresponding to recesses 329, 330 to permit space for the propulsionmotor 620A and the shunt motor 698. Shunt motor 698 is supported by amotor support 630 viewed in FIGS. 6, 6B and 9. Motor support 630 isaffixed to base plate 311. Also illustrated in FIG. 3E is a recessedsurface 324 which allows space for wiring from the sensors 106 throughthe conduit sensor with magnetic shunt 101.

FIG. 3F is another schematic perspective view 300F of the second backingbar weldment 302 of the conduit sensor with magnetic shunt illustratingsome of the features of the second backing bar weldment 302 in moredetail. Recesses 329, 330 are illustrated well in FIG. 3F. Slot 328 isillustrated but performs no function, the same being a remnant of theprocess of manufacturing the second backing bar weldment. FIG. 3G is anend view 300G of the second backing bar weldment 302 of the conduitsensor 101 with magnetic shunt illustrating cylindrical housing 326 inthe second backing bar weldment 302 and passageway 331. Cylindricallyshaped housing 326 terminates in an end surface 326E. A circular opening326C resides in end surface 326E and supports the rotor end 590 asillustrated in FIGS. 5, 5A and 5B. Cylindrically shaped housing 326 istypical of cylindrically shaped housing 327 illustrated in FIGS. 5, 5Aand 5B and is typical of cylindrically shaped housings 426, 427 in thefirst backing bar weldment 301. Passageway 331 extends through thesecond backing bar weldment 302 and houses the propulsion shaft 550 asillustrated in FIGS. 5, 5A, 5B, 10 and 10A.

Referring back to FIG. 3, first end gear box half 305 and first end gearbox half 306 are illustrated in FIG. 3 and combine to form the first endgear box which is fixed to the first and second backing bar weldments301, 302. Gear box half 306 is fixed to gear box half 305, secondbacking-bar weldment 302 and end plate 309. In the same way, gear box305 is fixed to gear box half 306, first backing-bar weldment 301 andend plate 309.

Referring still to FIG. 3, second end gear box half 307 and second endgear box half 308 combine to form the second end gear box which is fixedto the second end. Gear box half 308 is fixed to gear box half 307,second backing-bar weldment 302 and end plate 310. In the same way, gearbox 308 is fixed to gear box 307, first backing-bar weldment 301 and endplate 310. Still additionally, first backing-bar weldment 301 and secondbacking-bar weldment 302 are fixed together.

Wheel wells 305A, 306A, 307A, 308A are illustrated in FIG. 3 and provideroom for wheels 107, 107A, 108, 108A to rotate. First end bottom plate309, second end bottom plate 310, and base plate 311 are illustrated inFIG. 3. Base plate 311 extends from the first end 105 to the second end104 and wraps around the end plates 309, 310. First end gear box, 305,306, and, second end gear box 307, 308 are affixed to base plate 311.

FIG. 3A is a schematic top view 300A of the conduit sensor device withmagnetic shunt 101. FIG. 3B is a schematic side view 300B of the conduitsensor with magnetic shunt. Base plate 311 includes a first end portion311A which wraps around the first end bottom plate 309. Base plate 311Aalso includes a second end portion 311B which wraps around the secondend bottom plate 310.

FIG. 3C is a schematic first end view 300C of the conduit sensor withmagnetic shunt. First end access port 340 in end 311A of base plate 311allows adjustment of a thrust bearing for the magnet drive shaft. FIG.3D is a schematic second end view 300D of conduit sensor with magneticshunt. Second end access port 341 in end 311B of base plate 311 allowsadjustment of a thrust bearing for the magnet drive shaft (shunt shaft)401. FIG. 3H is a schematic perspective view 300H of the first end gearbox half 306 of the conduit sensor with magnetic shunt illustratingbearing well 306A, semi-circular shunt gear housing 306B, semi-circulardrive gear housing 306C, and bearing well 306D. Bearing well 306A housesbearing 516. See FIGS. 5 and 5A.

Referring to FIG. 3H, reference numeral 389 indicates a shoulder againstwhich bearing 901 resides. See FIG. 9 wherein shaft bearings 901 and 902are illustrated. Upper shoulder 306K in the semi-circular shunt gearhousing 306, limits upper movement of vertical shunt worm 612. Theshoulders 306K, 306L, 306M, 306N in gear box half 306 meet adjacentcorresponding unnumbered shoulders in gear box half 305 illustrated inFIG. 3J. FIG. 3J is a schematic perspective view 300J of the first endgear box half 305 of the first end of the conduit sensor device withmagnetic shunt. FIG. 3J illustrates the semi-cylindrical shunt gearhousing 305B and semi-cylindrical drive gear housing 305C. Housings306B, 305B reside adjacent each other and define the shunt worm 612housing. Housings 306C, 305C reside adjacent each other and definepropulsion worm 605 housings. Slot 305S supports bearing 416 whichsupports worm 402 mounted on shaft 401. Shoulder 305F defines theopening 305D in which drive gear 680 resides. FIG. 3K is a schematicperspective view 300K of the first half 305 of the gear box of the firstend of the conduit sensor device with magnetic shunt. Shoulder 305Hdefines seat 305L in which drive shaft bearing 902 resides. See FIGS. 9and 9C. Shoulder 305J defines another diameter in the first half of gearbox 305 and reference numeral 305W is the bearing well for bearing 412.See FIGS. 4 and 4A. Reference numeral 305E indicates the end of theopening which begins with bearing well 305A. Reference numeral 305indicates the passageway for the wheel drive shaft. Reference numeral305R indicates the opening for shunt shaft 401 and worm 402 in gear boxhalf 305.

Referring to FIGS. 3K, 4, 4A, 7, 7A, 7B, 7C, 7F and 7G, vertical slot340S receives pin 415S of partial cylinder 402C and prevents rotation ofthe partial cylinder 402C with respect to the first half 305 of the gearbox. It is necessary to restrain rotation of the partial cylinder 402Cso as to enable adjustment of thrust bearing 402B.

FIGS. 7A and 7C illustrate the partial cylinder 402C in cross-section.Magnet drive shaft 401 includes an end portion 401F which engages thrustbearing 402B. Bearing 402B is threadably adjusted as threaded stud 402Nis turned by a suitable tool such as a screw drive or hex headed wrenchwhich mates with grip 402G of the threaded stud 402N. Threaded stud 402Nincludes a curved surface 419C which engages bearing 402B. Partialcylinder 402C includes a stepped bore 402R therethrough. Bore 402R has arelatively larger diametrical section which houses thrust bearing 402B.Bore 402R also includes a relatively smaller diametrical threadedsection 402T which interengages threaded stud 402N.

FIGS. 7A and 7E illustrate the partial cylinder 403C in cross-section.Magnet drive shaft 401 includes an end portion 401S which engages thrustbearing 402B. Bearing 402B is threadably adjusted as threaded stud 403Nis turned by a suitable tool such as a screw drive or hex headed wrenchwhich mates with grip 403G of the threaded stud 403N. Threaded stud 403Nincludes a curved surface 420C which engages bearing 403B. Partialcylinder 403C includes a stepped bore 403R therethrough. Bore 403R has arelatively larger diametrical section which houses thrust bearing 403B.Bore 403R also includes a relatively smaller diametrical threadedsection 403T which interengages threaded stud 403N.

FIG. 7F is a top view 700 F of partial cylinder 402C which providesthrust bearing support for the magnet drive shaft 401. FIG. 7G is an endview 700G of the partial cylinder 402C which provides thrust bearingsupport for the magnet drive shaft. Partial cylinder 403C has identicalcharacteristics and, as such, is not separately described. Surface 402Zis flat and provides room for gear 608 as illustrated in FIGS. 9 and 9A.Also see FIGS. 7B and 7D. FIG. 7D illustrates the partial cylinder 403Cand flat surface 403Z.

FIG. 9 is a schematic top view 900 of the conduit sensor with magneticshunt with the backing bar weldments and the gear boxes removedillustrating the first magnet rotor assembly, second magnet rotorassembly, third magnet rotor assembly and fourth magnet rotor assembly.FIG. 9A is a schematic bottom view 900A of the first end of FIG. 9.

Referring to FIGS. 3C, 3D, and 4, access ports 340, 341 enableadjustment of the partial cylinders 402, 403 by rotating threaded studs,402N, 403N clockwise in bores 402T, 403T forcing the partial cylindersoutwardly into engagement with the ends 311A, 311B. The threaded studs402N, 403N may be adjusted at the same time so that approximately thesame amount of adjustment may occur on the first and second ends ofmagnet drive shaft 401. In other words, given the intermeshing of worms402, 403 with their respective worm wheels 614, 635 and given themeshing of the shaft mounted gear 404 with the motor drive gear 631, theshaft 401 must be positionally supported equally from both the first andsecond ends. Loctite may be used to secure the threaded connectionagainst vibration. Alternatively, if left handed threaded are used inthe bores and on the adjusting threaded nuts, the adjustment may be madeby turning the threaded studs counterclockwise. Pin 415S is guided invertical slot 340S and prohibits rotation of partial cylinder 402C sothat it may be adjusted into engagement with end 311A of the base plate311. At the second end of the device, pin 418S is guided in verticalslot 341S prohibiting rotation of partial cylinder 403C so that it maybe adjusted into engagement with end 311B of base plate 311.

Referring to FIGS. 3H, 3I, 6, and 6A, bearing seat 306L supports upperbearing 610 for shunt shaft 611 and shunt worm drive 612. Upper bearing610 supports drive shaft 611. Vertical shunt worm 612 is affixed todrive shaft 611 by pin 613 as illustrated in FIG. 6A. Vertical shuntworm 612 and vertical drive worm 614 include slots therein as bestviewed in FIG. 6A. FIG. 6 is a schematic cross-sectional view 600 takenalong the line 6-6 of FIG. 3A. FIG. 6A is an enlargement 600A of thefirst end portion 601 of the conduit sensor and magnetic shunt device.Vertical shunt worm 612 is restrained by shoulder 306K against upwardmovement.

Referring to FIG. 6A, bearing 609A is supported by shoulder 309S ofbottom plate 309. Similarly, bearing 609 is supported by shoulder 399Sof bottom plate 309. Spacer 615 resides between bearing 609A and shuntworm wheel 614. Spacer 615A resides between vertical shunt worm 612 andupper bearing 610. Shunt worm wheel 614 is driven by shaft driven worm402 as illustrated in FIGS. 4 and 4A. Worm wheel 614, drive shaft 611,and vertical shunt worm 612 are affixed to each other by pin 613 and,thus, all three components 614, 611, 612 rotate together.

Referring to FIG. 6A, spacer 617 resides between bearing 609 and driveworm wheel 608. Spacer 617A resides between vertical drive worm 605 andupper bearing 603. Drive worm wheel 608 is driven by shaft driven worm558 as illustrated in FIGS. 5, 5A, 9, 9A, and 9C. Worm wheel 608,vertical drive shaft 604, and vertical shunt drive 605 are affixed toeach other by pin 606 and, thus, all three components 608, 604, 605rotate together.

Referring to FIGS. 5A and 6A, propulsion motor 620A drives output shaftgear 620 which, in turn, drives spur gear 555 mounted on the propulsiondrive shaft 555. Worm 558 is affixed to propulsion drive shaft 550 androtates therewith. Worm wheel 558 is affixed to propulsion drive shaft550 and as drive shaft 550 rotates, worm wheel 558 rotates, drive wormwheel 608 rotates, and, vertical drive worm 605 rotates driving helicalgear 680. Rotation of helical gear 680 by drive worm 605 causes rotationof wheels 107, 107A which propel the conduit sensor device 101.Operation of the propulsion drive system is explained in greater detailhereinbelow.

Referring to FIGS. 6B and 5A, shaft 550 also drives worm wheel 551located at the second end of the device. As drive shaft 550 rotates,worm wheel 551 rotates, drive worm wheel 644 rotates, and vertical worm643 rotates driving helical gear 682. Rotation of helical gear 682 byvertical drive worm 643 causes rotation of wheels 108, 108A which propelthe conduit service device 101.

FIG. 9 is a schematic top view 900 of the conduit sensor device withbacking bar weldments 301, 302 and the gear boxes removed 305, 306, 307,308. Helical gears 414, 514 are viewed in FIGS. 9 and 9C. The top viewis taken from the direction of the pipe (not shown in FIG. 9) radiallyinwardly. Magnet rotor assemblies 991, 992, 993, 994 are illustratedwithout the backing bar weldments 301, 302 which house the magnet rotorassemblies. Backing bar weldments 301, 302 are magnetically conductiveenabling the magnetic field to pass freely therethrough depending on theorientation of the magnets of the magnet rotor assemblies. The first endof the conduit sensor device is the left end when viewing FIGS. 9, 9Aand 9C, the first end having magnet rotor assemblies 991, 992 and thegearing system 402, 414, 514, 555, 558, 605, 608, 612, 614, 620, 680proximate those rotor assemblies. See FIG. 9A, a schematic bottom viewof the first end of FIG. 9, to view the propulsion motor output gear620A and the propulsion shaft 550 with spur gear 555 mounted thereto.

The second end of the conduit sensor device is the right end whenviewing FIGS. 9, 9B and 9D, the end having magnet rotors assemblies 993,994 and the gearing system 403, 404, 408, 548, 551, 635, 636, 643, 644,682 proximate those rotor assemblies. See FIG. 9B, a schematic bottomview of the second illustrating shunt motor shaft output gear 631driving spur gear 404 mounted on shunt shaft 401.

Referring to FIG. 9, first magnet rotor assembly 991 includes pins 525P,526P, 527P, 528P which are press-fit through corresponding unnumberedholes in the top portion 525T and bottom portion 525B. Magnet rotorassembly 992 includes pins 421P, 422P, 423P, 424P which are press-fitthrough corresponding unnumbered holes in the top portion 421T andbottom portion 421B. Pins 525P, 526P, 527P, 528P are illustrated well inFIG. 9C as are pins 421P, 422P, 423P, 424P.

FIG. 9C is a schematic perspective view 900C of the first end of FIG. 9illustrating the gear drive system 402, 414, 514, 555, 558, 605, 608,612, 614, 620, 680 of the first end of the conduit sensor devicetogether with the first end magnet rotor assemblies 991, 992. Also seeFIG. 9A to view gears 555, 620. First magnet rotor assembly 991 includespermanent magnets 525, 526, 527 and 528 locked together by first rotorshaft end 515 proximate the gear drive system, top portion 525T of therotor assembly, bottom portion of the rotor assembly and the rotor shaftend 590 distally located with respect to the gear drive system. Firstmagnet rotor assembly 991 is housed in cylindrical housing 326 of secondbacking bar weldment 302 as illustrated in FIGS. 3E, 3F and 5. Thirdmagnet rotor assembly 992 includes permanent magnets 421, 422, 423, and424 locked together by third rotor shaft end 413 proximate the geardrive system, top portion 421T of the rotor assembly, bottom portion421B of the rotor assembly and the rotor shaft end 411 distally locatedwith respect to the gear drive system. Third magnet rotor assembly 992is housed in cylindrical housing 426 of first backing bar weldment 301as illustrated in FIGS. 4 and 4A. Still referring to FIG. 9C, the northpoles 525N, 526N, 527N, 528N of the magnets of first magnet rotorassembly 991 are oriented facing upwardly (toward the pipe to beinspected) and, similarly, the north poles 421N, 422N, 423N and 424N ofthe magnets of third magnet rotor assembly 992 are oriented facingupwardly. The south poles 525S, 526S, 527S, 528S of the magnets of firstmagnet rotor assembly 991 are oriented facing downwardly. The southpoles of 421S, 422S, 423S and 424S of the magnets of third magnet rotorassembly 992 are oriented facing downwardly. Reference is made to FIGS.5 and 5A, to view the south poles 525S, 526S, 527S, 528S of the magnetsof first magnet rotor assembly 991.

FIG. 9A is a bottom schematic view 900A of the first end of FIG. 9illustrating the gearing system, first magnet rotor assembly 991, andthird magnet rotor assembly 992. Bottom 421B of third magnet rotorassembly 992 and bottom 525B of first magnet rotor system 991 areillustrated in FIG. 9A. Propulsion motor support 616 is affixed to thebase plate 311 and supports centrally located propulsion motor 620A.Propulsion motor driven spur gear 620 drives shaft spur gear 555. Shaftspur gear 555 includes an integral collar with a set screw therein foraffixation to propulsion drive shaft 550. Helical gear 514 which iscoupled to and drives first magnet rotor assembly 991 is illustratedmounted on first rotor shaft end 515 proximate the gear drive system.Third helical gear 414 which is coupled to and drives third magnet rotorassembly 992 is illustrated mounted on the third rotor shaft end 413proximate the gear drive system. Bearings 516, 412, support the magnetrotor assemblies 991, 992, as they are mounted in gear box halves, 306,305 respectively. Referring to FIGS. 4, and 4A, third magnet rotorassembly 992 is illustrated with bearing 412 mounted in bearing seat305W of gear box half 305 and fourth magnet rotor assembly 994 isillustrated with bearing 407 mounted in bearing seat 307X of gear boxhalf 307.

FIG. 9E is an exploded perspective view 900E of fourth magnet rotorassembly 994 of the second end. Fourth magnet rotor assembly 994 istypical of magnet rotor assemblies 991, 992 and 993. FIG. 9F is anexploded perspective view 900F of the rotor assemblies 993, 994 of thesecond end. The structure illustrated in FIG. 9E of fourth magnet rotorassembly 994 is repeated in FIG. 9F. FIG. 9E is slightly larger andeasier to read. Referring to FIG. 9E, fourth magnet rotor assembly 994is illustrated wherein rotor shaft end 470 proximate the second end gearsystem is shown in an exploded perspective. Rotor shaft end 470 includesretaining slot 471 for magnet 437, another retaining slot 472 for magnet437, a circumferentially shaped lip 473, a shaft portion 474 whichincludes at least two diameters, and, one portion of the shaft 474includes a locking flat portion 475. Flat portion 475 engages areciprocally shaped flat portion 476 in the collar of helical gear 408.The top portion 434T and the bottom portion 434B of the fourth magnetrotor assembly 994 includes a semi-circumferential 471C lip which fitsinto the circumferentially shaped lip 473 of the rotor shaft end 470.

Fourth magnet rotor assembly 994 includes magnets 434, 435, 436, 437secured between a top 434T and a bottom 434B portion. Pins 434P, 435P,436P and 437P are press-fit into corresponding through holes 481, 482,483, 484 in the top portion 434T and the bottom portion 434B of theassembly. Magnets 434, 435, 436, 437 include holes 434H, 435H, 436H and437H which permit passage of the pins therethrough. The north poles ofthe magnets 434N, 435N, 436N, 437N as well as the south poles of themagnets 434S, 435S, 436S, and 437S are illustrated in FIG. 9E. The southpoles of the magnets 434S, 435S, 436S and 437S are illustrated as facingupwardly in the direction of the pipe to be inspected. See FIGS. 4 and4A for a schematic view of the orientation of the magnets 434, 435, 436,437. Rotor shaft end 410 distally located with respect to the gear drivesystem secures the fourth magnet rotor assembly 994 together. Snap-ring410S locks rotor shaft end 410 in place between upper shoulder 434U inthe top portion 434T and the lower shoulder 434L in the bottom portion434B. Rotor shaft 410 includes a cylindrical end portion which residesin backing bar weldment 301 as illustrated in FIGS. 4 and 4A. Circularopening 410D is larger than the diameter of end 410 and supports fourthmagnet rotor assembly 994. Each magnet rotor assembly includes abearing. One such bearing 407 is illustrated in FIG. 9E which resides inbearing seat 307X of gear box half 307 and supports the magnet rotorassembly 994. See FIGS. 4 and 4A.

FIG. 9F is an exploded perspective view 900F of the rotor assemblies993, 994 of the second end. Referring to FIG. 9F the second magnet rotorassembly 993 is illustrated wherein rotor shaft end 549 proximate thesecond end gear system is shown in exploded perspective. Rotor shaft end549 includes retaining slot 571 for magnet 533, another retaining slot572 for magnet 533, a circumferentially shaped lip 573, a shaft portion574 which includes at least two diameters, and, one portion of the shaft574 includes a locking flat portion 575. Flat portion 575 engages areciprocally shaped flat portion 576 in the collar of helical gear 548.The top portion 530T and the bottom portion 530B of the second magnetrotor assembly 993 includes a semi-circumferential 571C lip which fitsinto the circumferentially shaped lip 573 of the rotor shaft end 549.

Second magnet rotor assembly 993 includes magnets 530, 531, 532, 533secured between a top portion 530T and a bottom portion 530B. Pins 530P,531P, 532P and 533P are press-fit into corresponding through holes 581,582, 583, 584 in the top portion 530T and the bottom portion 530B of theassembly. Magnets 530, 531, 532, 533 include holes 530H, 531H, 532H and533H which permit passage of the pins therethrough. The north poles ofthe magnets 530N, 531N, 532N, 533N as well as the south poles of themagnets 530S, 531S, 532S, and 533S are illustrated in FIG. 9F. The southpoles of the magnets 530S, 531S, 532S and 533S are illustrated as facingupwardly in the direction of the pipe to be inspected. See FIGS. 5 and5A for a schematic view of the orientation of the magnets 530, 531, 532,533. Rotor shaft end 491 distally located with respect to the gear drivesystem secures the second magnet rotor assembly 993 together. Snap-ring491S locks rotor shaft end 491 axially in place between upper shoulder530U in the top portion 530T and the lower shoulder 530L in the bottomportion 530B. Rotor shaft 591 includes a cylindrical end portion whichresides in backing bar weldment 302 as illustrated in FIGS. 5 and 5A.Circular opening 591D is larger than the diameter of end 591 andsupports third magnet rotor assembly 993. Each magnet rotor assemblyincludes a bearing. One such bearing 547 is illustrated in FIG. 9F whichresides in bearing seat 308X of gear box half 308 and supports themagnet rotor assembly 993.

Gear box halves 305, 306 are connected together and house the gearsystems illustrated in FIGS. 6, 6A, 9, 9A, and 9C. As stated previously,the gear boxes are secured to each other, to first and second backingbar weldments 301, 302, to bottom plate 309 and to the first end of baseplate 311A by screws and/or other attachment means.

Gear box halves 308, 307 are connected together and house the gearsystems illustrated in FIGS. 6, 6B, 9, 9B, and 9D. As stated previouslyin regard to the gear box halves 306, 305, the gear box halves 308, 307are similarly secured to each other, to first and second backing barweldments 301, 302, to bottom plate 310 and to the second end of baseplate 311B by screws and/or other attachment means.

FIG. 3L is a schematic plan view 300L of the wheel propulsion driveshaft 681 of the first end together with the worm wheel/worm drive gear680. Drive worm gear 680 includes an integral collar 680F which isaffixed to the drive shaft 681. FIG. 3M is a schematic plan view 300M ofthe wheel propulsion drive shaft 681 of the first end wherein shoulders681S, 681H restrain movement of bearings 901, 902. Bearings 901, 902 areillustrated in FIGS. 9, 9A and 9C.

FIG. 3N is a schematic perspective view 300N of the bottom plate 309 ofthe first end of conduit sensor device with magnetic shunt. Slot 309A infirst end gear box bottom plate 309 houses shunt shaft 401 and worm 402affixed thereto. Slot 309B in first end gear box bottom plate 309 housespropulsion shaft 550 and worm 558 affixed thereto. Slot 309B is adjacentslot 306S in gear box half 306. Together slots 309B and 306S form ahousing/passageway for the propulsion shaft 550 and worm 558. Slot 309Ais adjacent slot 305S in gear box half 305 and these together form ahousing/passageway for shunt shaft 401 and worm 402.

Referring to FIGS. 3N and 6A, shoulder 309S supports lower bearing 609Afor shunt worm wheel 614 which drives vertical shunt worm 612. Shoulder399S supports lower bearing 609 for drive worm wheel 608 which drivesvertical drive worm 605. Shoulder 309G extends to cylindrical wall 309W.Cylindrical wall 309W in base plate 309 provides room for the rotationof shunt worm wheel 614 as it is diametrically larger than the shuntworm wheel 614. Shoulder 309H extends to cylindrical wall 309C.Cylindrical wall 309C in base plate 309 provides room for the rotationof drive worm wheel 608 as it is diametrically larger than the driveworm wheel 608. FIG. 3O is another schematic perspective view 300O ofthe bottom plate 309 of the first end of conduit sensor device withmagnetic shunt illustrating the same features just described.

FIG. 9D is a schematic perspective view 900D of the second end of FIG.9. FIG. 9B is a schematic bottom view 900B of the second end of FIG. 9.FIG. 6B is an enlargement 600B of a portion of FIG. 6.

Referring to FIGS. 6 and 6B, a bearing seat supports upper bearing 637.Shunt shaft 638 and shunt worm drive 636 are supported by bearings 637,633. Upper bearing 640 supports drive shaft 639. Vertical shunt worm 643is affixed to drive shaft 639 by pin 642 as illustrated in FIG. 6B.Vertical shunt worm wheel 635 and vertical drive worm 636 include slotstherein as best viewed in FIG. 6B. Vertical drive worm 643 is restrainedby a shoulder in gear box 602 against upward movement.

Referring to FIG. 6B, bearing 633 is supported by a shoulder of bottomplate 310. Similarly, bearing 646 is supported by a shoulder of bottomplate 310. Spacer 634 resides between bearing 633 and shunt worm wheel635. Spacer 634A resides between vertical shunt worm 636 and upperbearing 637. Shunt worm wheel 635 is driven by shaft driven worm 403 asillustrated in FIGS. 4 and 4A. Worm wheel 635, drive shaft 638, andvertical shunt worm 636 are affixed to each other by pin 641 and, thus,all three components 635, 638, 636 rotate together.

Referring to FIG. 6B, shunt motor 698 includes shaft 698S which drivesoutput shaft gear 631 which, in turn, drives spur gear 406 affixed toshunt shaft 401. See FIGS. 4 and 4A to view spur gear 406. Worm 403 isaffixed to shunt shaft 401 and as shunt shaft 401 rotates, worm 403rotates, shunt worm wheel 635 rotates, and, vertical shunt worm 636rotates driving helical gears 408, 548. For counter clockwise rotationof shunt shaft 401 when viewed from the perspective of the first end,90° rotation of helical gears 408, 548 by shunt worm 636 causes rotationof second end magnet rotor assemblies 993, 994 in opposite directionsrepositioning the magnets such that north poles of the second magnetrotor assembly 993 face north poles of fourth magnet rotor assembly 994.See FIGS. 10 and 10A. For clockwise rotation of shaft 401 when viewedfrom the perspective of the first end of the device, 90° rotation ofhelical gears 408, 548 by shunt vertical worm 636 causes rotation ofsecond end magnet rotor assemblies 993, 994 in opposite directionsrepositions the magnets such that south poles of the magnet rotorassembly 993 face south poles of the fourth magnet rotor assembly 994.

FIG. 9D is a schematic perspective view 900D of the second end of FIG. 9illustrating the gear drive system 403, 404, 408, 548, 551, 635, 636,643, 644, 682 of the second end of the conduit sensor device 101together with the magnet rotor assemblies 993, 994 residingsubstantially at the second end of the device. Also see FIG. 9B. Secondmagnet rotor assembly 993 includes permanent magnets 530, 531, 532, 533locked together by second end rotor shaft end 549 proximate the geardrive system, top portion 530T of the rotor assembly, bottom portion ofthe rotor assembly and the rotor shaft end 591 distally located withrespect to the gear drive system. Fourth magnet rotor assembly 994includes permanent magnets 434, 435, 436, 437 locked together by secondrotor shaft end 470 proximate the gear drive system, top portion 434T ofthe rotor assembly, bottom portion 434B of the rotor assembly and therotor shaft end 410 distally located with respect to the gear drivesystem. Still referring to FIG. 9D, the south poles 530S, 531S, 532S,533S of the magnets of second magnet rotor assembly 993 are orientedfacing upwardly (toward the pipe to be inspected) and, similarly, thesouth poles 434S, 435S, 436S and 437S of the magnets of fourth magnetrotor assembly 994 are oriented facing upwardly. The north poles 530N,531N, 532N, 533N of the magnets of second magnet rotor assembly 993 areoriented facing downwardly. The north poles 434N, 435N, 436N and 437N ofthe magnets of fourth magnet rotor assembly 994 are oriented facingdownwardly. Reference is made to FIGS. 5 and 5A, to view the north poles530N, 531N, 532N, 533N of the magnets of second magnet rotor assembly993.

FIG. 9B is a bottom schematic view 900B of the second end of FIG. 9illustrating the gearing system, second magnet rotor assembly 993, andfourth magnet rotor assembly 994. Bottom 434B of fourth magnet rotorassembly 994 and bottom 530B of second magnet rotor system 993 areillustrated in FIG. 9B. Shunt motor support 630 is affixed to the baseplate 311 and supports centrally located shunt motor 698. Shunt motordriven spur gear 631 drives shaft spur gear 404. Shaft spur gear 404includes an integral collar with a set screw therein for affixation toshunt shaft 401. Helical gear 548 which drives second magnet rotorassembly 993 is illustrated and is mounted on second end rotor shaft 549proximate the gear drive system. Fourth helical gear 408 which drivesfourth magnet rotor assembly 994 is illustrated and is mounted on thesecond end rotor shaft proximate the gear drive system. See FIG. 9F.Bearings 547, 407, support the magnet rotor assemblies 993, 994, as theyare mounted in gear box halves, 307, 308 respectively. Referring toFIGS. 4 and 4A, fourth magnet rotor assembly 994 is illustrated withbearing 407 mounted in bearing seat 307X of gear box half 307. Referringto FIGS. 5 and 5A, second magnet rotor assembly 993 is illustrated withbearing 547 mounted in bearing seat 308X of gear box half 308.

FIG. 7 is a plan view 700 of magnet drive shaft 401, first end worm 402,spur gear 404 affixed to shaft and second end worm 403. Bearings 416,406 support shaft 401 as best viewed in FIGS. 4 and 4A. Snap rings 416S,417S restrain bearing 416 against axial movement on shaft 401. Bearing416 resides in gear box half 305 and bottom plate 309. Bearing 406resides in gear box half 307 and bottom plate 310. FIG. 4 iscross-sectional view 400 taken along the line 4-4 of FIG. 3A. Line 4-4is taken along the centerline of magnetic shunt shaft 401. FIG. 4A is across-sectional view 400A taken along the line 4-4 of FIG. 3A. First endworm 402 is restrained in place by shoulder 402S and pin 415. Pin 415extends through worm 402 and shaft 401. Pin 415 prevents rotation ofworm 402 with respect to shaft 401. Pin 415 is press-fit into a hole inshaft 401. Pin 415 passes through worm 402 and restrains worm 402against axial movement with respect to shaft 401. Shoulder 402S alsorestrains worm 402 against axial movement.

Still referring to FIG. 7, spur gear 404 includes an integral collarwith a set screw 438S for affixing the collar against rotation withrespect to magnet drive shaft 401. Snap rings 438, 439 secure spur gear404 axially with respect to shaft 401. Snap rings 439 and 453S securebearing 406 against axial movement with respect to shaft 401. Second endworm 403 is affixed to magnet drive shaft 401 in the same way that firstend worm 402 is affixed to shaft 401. Pin 403P is press fit into a holein shaft 401 and restrains the worm 403 against axial movement alongshaft 401. Pin 403P extends through worm 403 and shaft 401 and preventsrotation of worm 403 with respect to shaft 401. Referring to FIG. 7E,shoulder 403S also restrains movement of second end worm 403 againstmovement on shaft 401.

Pins 415 and 403P lock worms 402, 403 to shunt shaft 401 and againstrotation with respect to the shunt shaft. Shunt shaft 401 is shorterthan the propulsion drive shaft 550. Shunt shaft 401 drives the magnetrotor assemblies 991, 992, 993 and 994. Shunt shaft 401 can rotateclockwise or counter clockwise. FIG. 7A is a cross-sectional view 700Ataken along the lines 7A-7A of FIG. 7. FIG. 7B is an enlargement 700B ofthe first end portion of FIG. 7. FIG. 7C is a cross-sectionalenlargement 700C of the first end portion of FIG. 7. FIG. 7D is anenlargement 700D of the second end portion of FIG. 7. FIG. 7E is across-sectional enlargement 700E of the second end portion of FIG. 7.

FIG. 8 is a plan view 800 of propulsion drive shaft 550, first end worm558, spur gear 555 affixed to shaft 550 and second end worm 551. Firstend worm 558 is secured to shaft 550 against rotation with respect tothe shaft by pin 557. Snap ring 559 secures the worm 558 againstleftward movement along shaft 550. Pin 557 resides in slot 557Sillustrated in FIG. 8A. Snap rings 556S, 561S secure bearing 560 axiallyin place on shaft 550. Snap rings 561S, 562S secure spur gear 555axially on propulsion drive shaft 550. Set screw 597 secures the spurgear 555 on shaft 550. Snap rings 554S, 553S secure bearing 553 axiallyon shaft 550. Bearings 560, 553 support shaft 550. Bearing 560 ismounted in gear box half 306 and bottom plate 309. Bearing 560 issupported by surface 309K in the bottom plate and by surface 306S ingear box half 306. Bearing 553 is mounted in gear box half 308 andbottom plate 310. See FIG. 5.

Still referring to FIG. 8, second end worm 551 is restrained againstrightward movement by snap ring 570S. Further, pin 552 is press fit intoshaft 550 within slot 552S in the second end worm 551. Some axialmovement of worm 551 is permitted. FIG. 8A is a cross-sectional view800A taken along the lines 8A-8A of FIG. 8. FIG. 8B is an enlargement800B of the first end portion of FIG. 8. FIG. 8C is a cross-sectionalenlargement 800C of the first end portion of FIG. 8. FIG. 8D is anenlargement 800D of the second end portion of FIG. 8. FIG. 8E is across-sectional enlargement 800E of the second end portion of FIG. 8.

FIG. 4 is cross-sectional view 400 taken along the line 4-4 of FIG. 3A.FIG. 4A is a cross-sectional view 400A taken along the line 4-4 of FIG.3A. Line 4-4 of FIG. 3A is not coincident with the centerline of magnetrotor assemblies 993, 994. Line 4-4 is taken along the centerline of theshunt shaft 401. Shunt shaft 401 resides slightly inwardly of thecenterline of magnet rotor assemblies 993, 994. Shunt shaft 401 issometimes referred to herein as the magnet drive shaft. FIG. 4illustrates the magnet rotor assemblies 992, 994 in their home or normalposition. In the normal position the magnets of third magnet rotorassembly 992 are oriented such that the north poles 421N, 422N, 423N,424N of the magnets 421, 422, 423, 424 are oriented facing upwardly. Inthe normal position the magnets of fourth magnet rotor assembly 994 areoriented such that the south poles 434S, 435S, 436S, 437S are orientedfacing upwardly. Reference is made to FIG. 4A, wherein magnetic field450 is illustrated for the normal position of magnet rotor assemblies992, 994. Pipe 499 is illustrated with field lines 450 passingtherethrough. As illustrated in FIG. 4A, wheels 107, 108 are illustratedin engagement with pipe 499. Sensors 106 detect abnormalities or defectsanywhere in the pipe. FIGS. 4 and 4A illustrate the magnetic field 450generated for the second and fourth magnet rotor assemblies. Themagnetic field generated 450A for the first and third magnet rotorassemblies is illustrated in FIG. 5A.

Still referring to FIGS. 4 and 4A, shunt shaft 401 is illustrated incross-section. Sometimes herein shunt shaft 401 is referred to as magnetshaft 401. FIG. 4A also illustrated worms 402, 403 and shaft bearings416, 406. Magnet rotor assemblies 992, 994 are illustrated withincylindrical housings 426, 427 in first backing bar weldment 301.Cylindrical opening 411D in backing bar weldment 301 is illustrated withrotor end 411 slip-fitted therein so as to permit rotation of rotor end411 with respect to the cylindrical opening 411D. Similarly, cylindricalopening 410D in backing bar weldment 301 is illustrated with rotor end410 slip-fitted therein so as to permit rotation of rotor end 410 withrespect to cylindrical opening 410D. Rotor assemblies 992, 994 aresubstantially cylindrically-shaped and have a diameter slightly smallerthan cylindrical housings 426, 427.

Operation of the magnetic shunt drive system is now described in greaterdetail.

Referring to FIGS. 4, 4A, 7, and 7A, the entire length of shunt shaft401 is viewed as is spur gear 404 affixed to shunt shaft 401 by snaprings 438, 439 and a set screw 438. FIGS. 7, 7A, 7B, 7C, 7D and 7Eillustrate the shunt shaft 401, worms 402, 403 and their mounting on theshunt shaft 401, bearings 406, 416 which support the shunt shaft 401,and spur gear 404. Spur gear 404 is affixed to shunt shaft 401 and, assuch, spur gear 404 rotates with shunt shaft 401. Spur gear 404 isdriven by shunt motor spur gear 631 as best viewed in FIG. 9B. FIG. 9Bis a bottom view of the second end of the conduit sensor device. Shuntmotor spur gear 631 is driven by shunt motor 698 as illustrated in FIG.6B. Referring to FIG. 4A, bearing 416 resides between support 305S inthe gear box half 305 and support 309L in bottom plate 309. Bearing 406similarly supports shaft 401 on the second end of the shaft between anunnumbered support in gear box 307 and an unnumbered support in bottomplate 310. Shunt shaft 401 rotates worm 402 at the first end of thedevice and shunt shaft 401 rotates worm 403 at the second end of thedevice. Worms 402, 403 are right handed.

Rotation of the shunt shaft 401 in the clockwise direction from theperspective of the first end is now described. Reaction of the gearingsystem which drives the magnet rotor assemblies 991, 992, 993, 994 isnow described as well in connection with the clockwise rotation of shuntshaft 401.

FIG. 9G is a schematic perspective view 900G similar to FIG. 9Cindicating rotation of the shunt drive shaft 401 in the clockwisedirection 950 as defined from the perspective of the first end of theconduit sensor device and also indicating rotation of the propulsiondrive shaft 550 in the clockwise direction 951 as defined from theperspective of the first end of the conduit sensor device.

Referring to FIGS. 9C and 9G, worm 402 engages right handed worm wheel614 at the first end of the device. Shaft 611 of worm wheel 614 isoriented 90° with respect to shaft 401 of worm 402. As worm 402 isrotated in clockwise direction 950 as shunt shaft 401 is rotated in aclockwise direction 950 when viewed from the first end of the conduitsensor device as illustrated in FIGS. 9C and 9G, then worm wheel 614 isrotated clockwise 952 when viewed from the perspective above shaft 611.Arrow 959 indicates the direction of travel of the helical gear teeth ofworm wheel 614 with respect to worm 402. Arrow 959 is substantiallytangent to worm wheel 614.

Still referring to FIGS. 9C and 9G, worm wheel 614 is locked to shaft611 and right handed vertical worm 612. Right handed helical gear 514 isin engagement with right handed vertical worm 612. Arrow 955 indicatesthe direction of travel of the helical gear teeth of helical gears 514,414 with respect to vertical worm 612. Arrow 955 is substantiallytangent to helical gears 514, 410. As shaft 611 of vertical worm 612 isrotated clockwise 952A, then helical gear 514 is rotated in theclockwise direction 953 along the shaft of helical gear 514. Verticalworm 612 has a helix angle of 10°. The first magnet rotor assembly ismounted at 7.5° with respect to horizontal. Therefore, helical gear 514has a helix angle of 17.5° which equals 10° plus 7.5°. Differentmounting angles may be used, different helix angles of the vertical wormmay be used and different helix angles of the helical gear may be used.

Referring to FIGS. 9C, 9G, and 5A, right handed helical gear 514 ismounted on a shaft portion of the first rotor shaft end 515.Simultaneously, as shaft 611 of vertical worm 612 is rotated in theclockwise direction viewed from above, then right handed third helicalgear 414 is rotated in the counter clockwise direction 954 along theshaft of third helical gear 414. Vertical worm 612 has a helix angle of10°. The second magnet rotor assembly is mounted at 7.5° with respect tohorizontal. Therefore, third helical gear 414 has a helix angle of 2.5°which equals 10° minus 7.5°. See FIG. 9G wherein the 7.5° angle isillustrated. See FIGS. 9C, 9G and 4A.

Referring to FIGS. 9C, 9G, 4A, and 5A, right handed third helical gear414 is mounted on a shaft portion of the third rotor shaft end 413.First magnet rotor assembly 991 is affixed to first rotor shaft end 515and rotates therewith and first rotor shaft end 515 is affixed to firsthelical gear 514 and rotates therewith. Third magnet rotor assembly 992is affixed to third rotor shaft end 413 and rotates therewith and thirdrotor shaft 413 is affixed to third helical gear 414 and rotatestherewith.

FIG. 9I is a schematic perspective view 900I of FIG. 9D indicatingrotation of the shunt drive shaft 401 in the clockwise direction 950 asdefined from the perspective of the first end of the conduit sensordevice and also indicating rotation of the propulsion drive shaft 550 inthe clockwise direction 951 as defined from the perspective of the firstend of the conduit sensor device.

Worm 403 engages right handed worm 635 at the second end of the conduitsensor device. See FIGS. 9D and 9I. Shaft 638 of worm 636 is oriented90° with respect to shaft 401 of worm 403. Arrow 968 indicates thedirection of travel of the teeth of helical worm wheel 635 with respectto helical worm 403. Arrow 968 is substantially tangent to worm wheel635. As worm 403 is rotated in clockwise direction 950, as shunt shaft401 is rotated in a clockwise direction 950, when viewed from the firstend of the conduit sensor device as illustrated in FIG. 9C, then wormwheel 635 is rotated clockwise 965 when viewed from the perspectiveabove shaft 638. Arrow 969 indicates the direction of travel of theteeth of helical gears 408, 548 with respect to vertical helical worm636. Arrow 969 is substantially tangent with respect to second helicalgear 548 and third helical gear 408. Worm wheel 635 is locked to shaft638 and right handed vertical worm 636. Right handed fourth helical gear408 is in engagement with right handed vertical worm 636. As shaft 638of vertical worm 636 is rotated clockwise 965A, then fourth helical gear408 is rotated in the clockwise direction 966 along the shaft of fourthhelical gear 408. Vertical worm 636 has a helix angle of 10°. The fourthmagnet rotor assembly is mounted at 7.5° with respect to horizontal.Therefore, fourth helical gear 408 has a helix angle of 17.5° whichequals 10° plus 7.5°. Right handed fourth helical gear is mounted on ashaft portion of the second rotor shaft end 470. Worm 636 engages secondhelical gear 548. Simultaneously, as shaft 638, and vertical worm 636are rotated in the clockwise direction 965A viewed from above, thenright handed second helical gear 548 is rotated in the counter clockwisedirection 967 along the shaft of second helical gear 548. Vertical worm636 has a helix angle of 10°. The third magnet rotor assembly is mountedat 7.5° with respect to horizontal as illustrated in FIG. 9I. Therefore,second helical gear 548 has a helix angle of 2.5° which equals 10° minus7.5°.

Right handed second helical gear 548 is mounted on a shaft portion ofthe second rotor shaft end 549. Fourth magnet rotor assembly 994 isaffixed to second rotor shaft end 470 and rotates therewith and secondrotor shaft 470 is affixed to fourth helical gear 408 and rotatestherewith. Second magnet rotor assembly 993 is affixed to second rotorshaft end 549 and rotates therewith and second rotor shaft end 549 isaffixed to second helical gear 548 and rotates therewith.

Rotation of the shunt shaft 401 in the counter clockwise direction fromthe perspective of the first end is now described. Reaction of thegearing system which drives the magnet rotor assemblies 991, 992, 993,994 is now described as well in connection with the counter clockwiserotation of shunt shaft 401.

FIG. 9H is a schematic perspective view 900H similar to FIG. 9Cindicating rotation of the shunt drive shaft 401 in the counterclockwise direction 970 as defined from the perspective of the first endof the conduit sensor device and also indicating rotation of thepropulsion drive shaft 550 in the counter clockwise direction 971 asdefined from the perspective of the first end of the conduit sensordevice.

Referring to FIGS. 9C and 9H, if shunt shaft 401 is rotated in theopposite direction, namely, counter clockwise 970 as indicated by arrow970 when viewed from the first end of the conduit sensor device asillustrated in FIGS. 9C and 9H, then worm wheel 614 rotates in a counterclockwise direction as indicated by arrow 972 when viewed from aboveshaft 611. When shaft 401 is rotated counter clockwise 970 as defined,vertical worm 612 rotates counter clockwise as indicated by arrow 972A,first helical gear 514 rotates counter clockwise as indicated by arrow973, and third helical gear 414 rotates clockwise as indicated by arrow974.

FIG. 9J is a schematic perspective view 900J similar to FIG. 9Dindicating rotation of the shunt drive shaft 401 in the counterclockwise 970 direction as defined from the perspective of the first endof the conduit sensor device and also indicating rotation of thepropulsion drive shaft 550 in the counter clockwise 971 direction asdefined from the perspective of the first end of the conduit sensordevice. FIG. 9J illustrates the gearing system and magnet rotorassemblies 993, 994 of the second end of the device.

Referring to FIGS. 9D and 9J, if shunt shaft 401 is rotated in thecounter clockwise 970 direction when viewed from the first end of theconduit sensor device as illustrated in FIG. 9C, then worm wheel 635rotates in the counter clockwise 975 direction when viewed above shaft638, and vertical worm 636 rotates in the counter clockwise 975Adirection since worm 636 is locked to shaft 638 and worm wheel 635. Whenshaft 401 is rotated counter clockwise 970 as defined, worm wheel 635rotates counter clockwise 975, fourth helical gear 408 rotates counterclockwise 976, and second helical gear 548 rotates clockwise 978. Arrow979 indicates the direction of travel of worm wheel 635 with respect toworm 403. Arrow 979 is substantially tangent to helical gear 408, 548.Arrow 980 indicates the direction of travel of worm wheel 644 withrespect to worm 551. Arrow 980 is substantially tangent to worm wheel644.

FIG. 10 is a cross-sectional view 1000 taken along the lines 10-10 ofFIG. 3. FIG. 10 illustrates the rotor assemblies 993, 994 in the normalor home position. In the normal or home position, the magnetic field 450is strongest. FIGS. 4A and 5A illustrate the magnetic fields 450, 450Aat their maximum extent. FIG. 4A illustrates rotor assemblies 992, 994and FIG. 5A illustrates magnet rotor assemblies 991, 993. FIG. 9 clearlyillustrates the rotor assemblies 991, 992, 993, 994 in their homeposition. FIG. 4A illustrates rotor assemblies 992, 994 in their homepositions. Magnets 421, 422, 423, 424 of third magnet rotor assembly 992are illustrated with their north poles 421N, 422N, 423N, 424N orientedfacing upwardly toward pipe 499. Magnets 434, 435, 436, and 437 offourth magnet rotor assembly 994 are illustrated with their south poles434S, 435S, 436S and 437S oriented facing upwardly toward pipe 499. FIG.5A illustrates magnet rotor assemblies 991, 993 in their home position.Magnets 525, 526, 527, 528 of rotor assembly 991 are illustrated withtheir north poles 525N, 526N, 527N, 528N oriented facing upwardly towardpipe 499. Magnets 530, 531, 532, 533 of second magnet rotor assembly 993are illustrated with their south poles 530S, 531S, 532S, 533S orientedfacing upwardly. FIGS. 4A and 5A illustrate magnet rotor assemblies 993,994 oriented in the same position as FIG. 10. FIG. 10 illustrates thetop portion 530T and the bottom portion 530B of second magnet rotorassembly 993, as well as magnet 530. Second magnet rotor assembly 993 isillustrated residing in cylindrically shaped housing 327 in backing barweldment 302.

Although not visible in FIG. 10, the diameter of second magnet rotorassembly 993 is smaller than the diameter of the cylindrically shapedhousing 327 such that second magnet assembly 993 rotates withoutengaging housing 327. Any incidental engagement that might occur isinsignificant and does not impede the rotation of the second magnetrotor assembly 993. Similarly, propulsion drive shaft 550 resides withinbore or passageway 331 in second backing bar weldment 302. The diameterof propulsion drive shaft 550 is less than the diameter of passageway331 and, therefore, propulsion drive shaft 550 rotates freely within thepassageway 331. Similarly, the shunt shaft 401 resides within passageway377. Passageway 377 extends from the first end of the backing barweldment 301 to the second end of the backing bar weldment 301 asillustrated in FIG. 4A. The diameter of the shunt shaft 401 is smallerthan the diameter of the passageway 377.

FIG. 10A is a cross-sectional view 1000A taken along the lines 10-10 ofFIG. 3, with shunt shaft 401 rotated counter clockwise and with therotor assemblies 993, 994 of the second end rotated 90° to the positionwhere the magnetic fields are cancelled. When shaft 401 is rotatedcounter clockwise as defined, worm wheel 635 rotates counter clockwise,fourth helical gear 408 rotates counter clockwise, and second helicalgear 548 rotates clockwise. See FIG. 9J. Then magnet rotor assemblies993, 994 and magnets 530, 434 are positioned in their second position asillustrated in FIG. 10A with sufficient rotation of shaft 401. Shaft 401is driven by the shunt motor 698 which drives shaft 698S which drivesshunt shaft output gear 631. See FIG. 6B. Shunt shaft output gear 631engages shunt shaft mounted gear 404. Shunt motor 698 may be a singledirection motor or the motor may be bidirectional. Shunt motor 698 maybe a stepper motor. Motor control is necessary to control thepositioning of the magnet rotor assemblies, and, hence the strength ofthe magnetic field between the first end and the second end of thedevice. A specific number of revolutions of the shunt drive shaft 401equates to a specific number of revolutions of the vertical worms 612,636. A specific number of revolutions of the vertical worm 612 equatesto a specific number of revolutions, or fractional part thereof, offirst helical gear 514 and third helical gear 414. Further, a specificnumber of revolutions of the vertical worm 636 equates to a specificnumber of revolutions, or fractional part thereof, of second helicalgear 548 and fourth helical gear 408. Therefore, control of the shuntshaft 401 dictates control and position of the magnet rotor assemblies991, 992, 993, 994. The control system is responsible for rotating themagnets between the first position, 0° rotation as shown in FIGS. 9, 9C,9D, 10, and 11 to the second position illustrated in FIGS. 5B, 10A, and11A, 90° rotation based on counter clockwise rotation of shunt shaft401.

Reference is made to FIGS. 4A and 5A wherein the field strengths 450,450A are illustrated at their maximum. FIG. 10A illustrates the positionof the magnet rotor assemblies 993, 994 as a result of counter clockwiserotation of shunt shaft 401 to the shunt position or cancellationposition. The position of the magnet rotor assemblies 991, 992, 993, 994is dependent on the positioning of shunt shaft 401 which drivesshaft-mounted worms 402, 403. The magnetic field 1001, 1002 of thesecond magnet rotor assembly 993 is shown in FIG. 10A. The magneticfield 1003, 1004 of the fourth magnet rotor assembly 994 is shown inFIG. 10A. In the position illustrated in FIG. 10A, the magnet rotorassemblies do not create a magnetic field in pipe 499; rather, themagnetic fields of the magnet rotor assemblies 993, 994 are shuntedmeaning there is no magnetic field between the first and second ends ofthe conduit sensor device as illustrated in FIGS. 4A and 5A.

Referring to FIGS. 10, 10A, 11, and 11A, reference numeral 1010signifies and indicates the rear or rearward portion of the conduitsensor device. Reference numeral 1011 signifies and indicates the frontor forward portion of the conduit sensor device. Reference numeral 1012signifies and indicates the central portion of the conduit sensordevice.

FIG. 11 is a cross-sectional view 1100 taken along the lines 11-11 ofFIG. 3. FIG. 11A is a cross-sectional view 1100 taken along the lines11-11 of FIG. 3 with the rotor assemblies 991, 992 of the first endrotated 90° with shunt shaft 401 rotated counter clockwise. See FIGS. 9Hand 9J.

When magnet rotor assemblies 993, 994 are driven to the shunt positionof FIG. 10A, the magnet rotor assemblies 991, 992 are simultaneouslydriven to the shunt position of FIG. 11A. Shunt shaft 401 drives themagnet rotor assemblies 991, 992 of the first end simultaneously withthe magnet rotor assemblies 993, 994 of the second end. FIG. 11A is across-sectional view 1100A taken along the lines 11-11 of FIG. 3 withthe rotor assemblies 993, 994 of the second end rotated 90° to theposition where the magnetic fields are cancelled. Reference is made toFIGS. 4A and 5A wherein the field strengths 450, 450A are illustrated attheir maximum.

When shaft 401 is rotated counter clockwise as defined and illustratedin FIGS. 9H and 9J, vertical worm 612 rotates counter clockwise, firsthelical gear 514 rotates counter clockwise, and third helical gear 414rotates clockwise. FIG. 11A illustrates the position of the magnet rotorassemblies 991, 992 as a result of counter clockwise rotation of shuntshaft 401 to the shunt position or cancellation position, for example a90° rotation of the magnet rotor assemblies. The terms “shunt position”and “cancellation position” are also known as the “second position.”FIGS. 9, 9C, 9D, 10, and 11 illustrate the magnet rotor assemblies 991,992, 993, and 994 in their first positions (0° rotation).

The magnetic field 1101, 1102 of the second magnet rotor assembly 993 isshown in FIG. 10A. The magnetic field 1103, 1104 of the fourth magnetrotor assembly 994 is shown in FIG. 11A. In the position illustrated inFIG. 11A, the magnet rotor assemblies do not create a magnetic field inpipe 499; rather, the magnetic fields of the magnet rotor assemblies991, 991 are shunted meaning there is no magnetic field between thefirst and second ends of the conduit sensor device as illustrated inFIGS. 4A and 5A.

The magnet rotor assemblies 991, 992, 993, 994 include top portions andbottom portions as described herein wherein the top and bottom portions,magnets and pins together with the rotor ends form the assemblies. Thetop and bottom portions of each of the magnet rotor assemblies 991, 992,993, 994 are ferromagnetic. Further, the first and second backing barweldments 301, 302 are ferromagnetic. First and second backing barweldments 301, 302 are made of 1008 steel capable of carrying a highermagnetic field than typical 1018 steel.

FIGS. 4A and 5A are schematic cross-sectional views of the conduitsensor device with magnetic field lines 450 illustrated. The inventionis not limited in any way by the size of the magnets or the magnet rotorassemblies.

Referring to FIGS. 4A and 5A, the home position of the rotatable magnetsis illustrated. The home position of the rotatable magnets is also shownin FIGS. 4 and 5. The pipe wall 499 is illustrated with a thickness andthe magnetic fields 450, 450A are illustrated passing entirely throughthe wall of the pipe 499.

FIG. 5 is a cross-sectional view 500 taken along the lines 5-5 of FIG.3A. Line 5-5 is taken along the centerline of the propulsion drive shaft550. FIG. 5A is a cross-sectional view 500A taken along the lines 5-5 ofFIG. 3A with a pipe in the view. FIG. 5B is a cross-sectional view 500Btaken along the lines 5-5 of FIG. 3A with rotor assemblies rotated 90°.No polarities of the magnets are noted in FIG. 5B as the magnets areshown in cross section as are the pins which hold the magnets in place.The pins are press-fitted into the top and bottom portions of the magnetrotor assembly. In the position illustrated in FIG. 5B, there is nomagnetic field between first magnet rotor assembly 991 and second magnetrotor assembly 993 as the magnetic fields have been shunted (canceled)as illustrated in FIGS. 10A and 11, and, as such there is no magneticfield shown in FIG. 5B.

Line 5-5 of FIG. 3A is not coincident with the centerline of magnetrotor assemblies 991, 993. Propulsion drive shaft 550 resides slightlyinwardly of the centerline of magnet rotor assemblies 991, 993.Propulsion drive shaft 550 is sometimes referred to herein as just thepropulsion shaft 550. FIG. 5 illustrates the magnet rotor assemblies991, 993 in their home or normal position. In the normal position themagnets of rotor assembly 991 are oriented such that the north poles525N, 526N, 527N, 528N of the magnets 525, 526, 527, 528 are orientedfacing upwardly. In the normal position the magnets of second magnetrotor assembly 993 are oriented such that the south poles 530S, 531S,532S, 533S are oriented facing upwardly. Reference is made to FIG. 5A,wherein magnetic field 450 is illustrated for the normal position ofmagnet rotor assemblies 991, 993. Pipe 499 is illustrated with fieldlines 450 passing therethrough. As illustrated in FIG. 5A, wheels 107,108 are illustrated in engagement with pipe 499. Sensors 106 detectabnormalities or defects anywhere in the pipe 499.

Still referring to FIGS. 5 and 5A, propulsion drive shaft 550 isillustrated in cross-section. FIG. 5A also illustrated worms 558, 551and shaft bearings 560, 553. Magnet rotor assemblies 991, 993 areillustrated within cylindrical housings 326, 327 in second backing barweldment 302. Cylindrical opening 590D in backing bar weldment 302 isillustrated with rotor end 590 slip-fitted therein so as to permitrotation of rotor end 590 with respect to the cylindrical opening 590D.Similarly, cylindrical opening 591D in backing bar weldment 302 isillustrated with rotor end 591D slip-fitted therein so as to permitrotation of rotor end 591D with respect to cylindrical opening 591D.Rotor assemblies 991, 993 are substantially cylindrically-shaped andhave a diameter slightly smaller than cylindrical housings 326, 327 inwhich they reside. The magnetic field 450A generated by the first magnetrotor assembly 991 and the second magnet rotor assembly 993 isillustrated in FIG. 5A. The magnetic field 450 generated by the secondmagnet rotor assembly 992 and the fourth magnet rotor assembly 994 isillustrated in FIG. 4A.

Still referring to FIGS. 5 and 5A, the entire length of propulsion driveshaft 550 is viewed as is spur gear 555 affixed to propulsion driveshaft 550 by snap rings 561S, 562S and a set screw 527. FIGS. 8. 8A, 8B,8C, 8D and 8E illustrate the propulsion drive shaft 550, worms 558, 551and their mounting on the propulsion drive shaft 550, bearings 560, 553which support the shunt shaft 550, and spur gear 555. Spur gear 555 isdriven by propulsion motor spur gear 620 as best viewed in FIG. 9A. FIG.9A is a bottom view of the first end of the conduit sensor device. Thepropulsion drive motor spur gear 620 is driven by the propulsion motor620A as illustrated in FIG. 6A. Referring to FIG. 5A, bearing 560resides between support 306S in the gear box half 306 and support 309Kin bottom plate 309. Bearing 553 similarly supports shaft 550 on thesecond end thereof between an unnumbered support in gear box 308 and anunnumbered support in bottom plate 310.

A process for modifying a magnetic field of a conduit sensor device isdisclosed. The conduit sensor is in proximity to a ferromagneticconduit. The steps of the process include: driving a shunt shaft havingfirst and second worms affixed thereto and rotating therewith; rotating,using the first worm, a first worm wheel and a first vertical wormaffixed thereto; rotating, using the first vertical worm, a firsthelical gear and a first magnet rotor assembly affixed to the firsthelical gear; rotating, using the second worm, a second worm wheel and asecond vertical worm affixed thereto; and, rotating, using the secondvertical worm, a second helical gear and a second magnet rotor assemblyaffixed to the second helical gear. Preferably, the process includesrotating, using the first vertical worm, a third helical gear and athird magnet rotor assembly affixed to the third helical gear; and,rotating, using the second vertical worm, a fourth helical gear and afourth magnet rotor assembly affixed to the fourth helical gear.

According to the process for modifying the magnetic field, the steps ofrotating the first, second, third and fourth magnet assemblies mayinclude rotating the magnet assemblies from a first position wherein amagnetic field exists between the first magnet assembly and the secondmagnet assembly and from a first position wherein a magnetic fieldexists between the third magnet assembly and the fourth magnet assemblyto a second position wherein no magnetic field exists between the firstmagnet assembly and the second magnet assembly and wherein no magneticfield exists between the third magnet assembly and the fourth magnetassembly.

According to the process for modifying the magnetic field, the shuntshaft may be rotated bidirectionally. The first, second, third andfourth magnet assemblies may be rotated 90° to their second position.Each of the magnet rotor assemblies includes a plurality of magnets andthe magnet rotor assemblies are housed and supported in first and secondbacking bar weldments. According to the process, the rotation of thefirst and third magnet rotor assemblies residing at a first end of thedevice and the rotation of the second and fourth magnet rotor assembliesresiding at a second end of the device is performed synchronously.

Alternatively according to the process the steps of rotating the first,second, third and fourth magnet assemblies may include rotating themagnet assemblies less than 90°: from a first position wherein a maximumstrength magnetic field exists between the first magnet assembly and thesecond magnet assembly; and, from a first position wherein a maximumstrength magnetic field exists between the third magnet assembly and thefourth magnet assembly, to an intermediate position wherein a lowerstrength magnetic field exists between the first magnet assembly and thesecond magnet assembly and wherein a lower strength magnetic fieldexists between the third magnet assembly and the fourth magnet assembly.

Operation of the propulsion drive system is now described in greaterdetail.

Referring to FIGS. 9, 9A, 9B, 9C and 9D, right handed worms 558, 551 aremounted on shaft 550. On the first end, worm 558 engages worm wheel 608.on the second end, worm 551 engages worm wheel 644.

Clockwise rotation of propulsion shaft 550 from the perspective of thefirst end is now described.

FIG. 9G is a schematic perspective view 900G of FIG. 9C indicatingrotation of the propulsion drive shaft 550 in the clockwise direction951 as defined and viewed from the perspective of the first end of theconduit sensor device.

Referring to FIGS. 9, 9C and 9G, as worm 558 rotates clockwise 951 whenviewed from the first end to the second end, worm wheel 608 rotatescounter clockwise 956 from the perspective of FIG. 9. Arrow 960indicates the direction of travel of the worm wheel 608 with respect toworm 558 when shaft 550 and worm 558 are rotated clockwise 951 asdefined herein. Arrow 960 is substantially tangent to worm 558. As shaft550 rotates clockwise 951, then vertical worm 605 rotates counterclockwise 957 from the perspective of FIG. 9, specifically, from abovethe first end. As worm 605 rotates counter clockwise 957 then gear 680rotates counter clockwise 958 along its shaft as viewed in FIGS. 9C and9G from right to left and in FIG. 6A. As gear 680 is affixed to wheelshaft 681, and as wheels 107, 107A are affixed to wheel shaft 681 androtate therewith, the conduit sensor device will be propelledrightwardly when viewing FIGS. 6, 6A, 6B and 9.

FIG. 9I is a schematic perspective view 900I similar to FIG. 9Dindicating rotation of the propulsion drive shaft 550 in the clockwisedirection 951 as defined from the perspective of the first end of theconduit sensor device.

Referring to FIGS. 9, 9D and 9I, if propulsion drive shaft 550 rotatesclockwise 951 when viewed from the first end toward the second end, thenworm 551 also rotates clockwise 951 as worm 551 is affixed to shaft 550.Worm 551 and worm wheel 644 driven by worm 551 are right handed.Vertical worm 643 and worm wheel 682 are left handed and these are theonly two left handed worm and worm wheel disclosed here. All other wormsand worm wheels are right handed. Vertical worm 643 and worm wheel 682are left handed so that worm wheels 680, 682 rotate in the samedirection. Other gearing arrangements and combinations may be used. Asworm 551 rotates clockwise 951 then worm wheel 644 rotates counterclockwise 961 when viewed from above the conduit sensor device asillustrated in FIGS. 9, 9D and 9I. Referring to FIG. 9B, a bottom viewof the second end of the conduit sensor device, reference is made toworm 551 in meshed engagement with worm wheel 644. From the perspectiveof FIG. 9B, worm wheel 644 rotates clockwise when worm 551 is rotatingclockwise with respect to the first end of the device. Arrow 964 in FIG.9I indicates the direction of travel of worm wheel 644 with respect toworm 551. Arrow 964 is substantially tangent to worm wheel 644.

Referring to FIGS. 9, 9D and 9I, as worm wheel 644 rotates counterclockwise from the perspective of FIG. 9, then vertical worm 643 rotatescounter clockwise 962 from the perspective of FIG. 9. As vertical worm643 rotates counter clockwise 962, then wheel gear 682 rotates counterclockwise 963 along its shaft as viewed from left to right in FIGS. 9Dand 9I. As gear 682 is affixed to wheel shaft 683, and as wheels 108,108A are affixed to wheel shaft 683 and rotate therewith, the conduitsensor device will be propelled rightwardly when viewing FIGS. 6, 6A, 6Band 9.

Counter clockwise rotation of the propulsion shaft 550 from theperspective of the first end is now described.

FIG. 9H is a schematic perspective view 900H similar to FIG. 9Cindicating rotation of the shunt drive shaft 401 in the counterclockwise direction 971 as defined from the perspective of the first endof the conduit sensor device and also indicating rotation of thepropulsion drive shaft 550 in the counter clockwise 971 direction asdefined from the perspective of the first end of the conduit sensordevice.

Referring to FIGS. 9, 9C and 9H, as worm 558 rotates counter clockwise971 when viewed from the first end to the second end, worm wheel 608rotates clockwise 985 from the perspective of FIG. 9. As shaft 550rotates counter clockwise 971, then worm 605 rotates clockwise 987 fromthe perspective of FIG. 9. Arrow 986 indicates the direction of travelof worm wheel 608 with respect to worm 558. Arrow 986 is substantiallytangent to worm wheel 608.

As worm 605 rotates clockwise 987, then gear 680 rotates clockwise 988along its shaft as viewed in FIGS. 9C and 9H. Reference numeral 987Aindicates the direction of travel of the teeth of worm wheel 680 withrespect to worm 605. Arrow 987 is substantially tangent to worm wheel680. As worm wheel 680 is affixed to wheel shaft 681, and as wheels 107,107A are affixed to wheel shaft 681 and rotate therewith, the conduitsensor device will be propelled leftwardly when viewing FIGS. 6, 6A, 6Band 9.

FIG. 9J is a schematic perspective view 900J similar to FIG. 9Dindicating rotation of the propulsion drive shaft 550 in the counterclockwise direction as defined from the perspective of the first end ofthe conduit sensor device.

Referring to FIGS. 9, 9D and 9J, if propulsion drive shaft 550 rotatescounter clockwise 971 when viewed from the first end toward the secondend, then worm 551 also rotates counter clockwise 971 as worm 551 isaffixed to shaft 550. As worm 551 rotates counter clockwise 971 thenworm wheel 644 rotates clockwise 981 when viewed from above the conduitsensor device as illustrated in FIGS. 9, 9D and 9J. Referring to FIG.9B, a bottom view of the second end of the conduit sensor device,reference is made to worm 551 in meshed engagement with worm wheel 644.From the perspective of FIG. 9B, worm wheel 644 rotates counterclockwise.

Referring to FIGS. 9, 9D and 9J, as worm wheel 644 rotates clockwisefrom the perspective of FIG. 9, then vertical worm 643 rotates clockwise982 from the perspective of FIG. 9. As vertical left-handed worm 643rotates clockwise, then left-handed worm wheel 682 rotates clockwise 983along its shaft, as viewed from left to right in FIGS. 9D and 9J. Arrow984 indicates the direction of travel of worm wheel 682 with respect tovertical left-handed worm 643. Arrow 984A indicating the direction oftravel of helical gears 408, 548 with respect to worm 636. As gear 682is affixed to wheel shaft 683, and as wheels 108, 108A are affixed towheel shaft 683 and rotate therewith, the conduit sensor device will bepropelled leftwardly when viewing FIGS. 6, 6A, 6B and 9.

A method of operating a conduit sensor device which propels the devicewithin a conduit includes the steps of: rotating a propulsion shafthaving first and second worms affixed thereto and rotating therewith;rotating, using the first worm, a first worm wheel and a first verticalworm affixed thereto; rotating, using the first vertical worm, a firstdrive wheel worm having a first drive wheel affixed thereto; rotating,using the second worm, a second drive worm wheel and a second verticalworm affixed thereto; and, rotating, using the second vertical worm, asecond drive worm wheel having a second drive wheel affixed thereto.Also, a step of: synchronizing the first and second drive wheels.

REFERENCE NUMERALS

-   100—perspective view of a plurality of conduit sensor device with a    plurality of sensors and magnetic shunts-   101—arrow pointing to one conduit sensor with magnetic shunt-   102—couplings-   103—tubular radial control mechanism-   103A, 103B—wire/rod for extending the conduit sensors-   104—arrow indicating second end of one conduit sensor with magnetic    shunt-   105—arrow indicating first end of one conduit sensor with magnetic    shunt-   106—electronic sensors used to detect anomalies and defects in pipe-   107A, 107B, 108A, 108B—propulsion wheels-   109—drive units-   200—enlargement of a portion of FIG. 1 illustrating the tubular    radial control mechanism and a conduit sensor with magnetic shunt-   201—spring-   300—perspective view of conduit sensor with magnetic shunt-   300A—top view of conduit sensor with magnetic shunt-   300B—side view of conduit sensor with magnetic shunt-   300C—first end view of conduit sensor with magnetic shunt-   300D—second end view of conduit sensor with magnetic shunt-   300E—perspective view of the second backing bar weldment of the    conduit sensor with magnetic shunt-   300F—another perspective view of the second backing bar weldment of    the conduit sensor with magnetic shunt-   300G—end view of the second backing bar weldment of the conduit    sensor with magnetic shunt-   300H—perspective view of the second half of the gear housing of the    first end of the conduit sensor with magnetic shunt-   300I—another perspective view of the second half of the gear housing    of the first end of the conduit sensor with magnetic shunt-   300J—is a perspective view of the first half of the gear box of the    first end of the conduit sensor device with magnetic shunt-   300K—is a perspective view of the first half of the gear box of the    first end of the conduit sensor device with magnetic shunt-   300L—is a plan view of the wheel propulsion drive shaft of the first    end together with the drive gear-   300M—is a plan view of the wheel propulsion drive shaft of the first    end.-   300N—perspective view of the bottom plate of the first end of    conduit sensor with magnetic shunt-   300O—another perspective view of the bottom plate of the first end    of conduit sensor with magnetic shunt-   301—first backing bar weldment-   302—second backing bar weldment-   303—first center roller-   304—second center roller-   305—first end gear box half-   305A—wheel well-   305B—semi-cylindrical shunt gear housing in the first end gear box    half 305-   305C—semi-cylindrical drive gear housing in the first end gear box    half 305-   305D—opening for gear 680-   305E—end surface in gear box half 305-   305F, 305H, 305J—shoulder-   305G—passageway for shaft-   305L—seat for propulsion wheel bearing 902-   305S—bearing support for shunt shaft bearing 416-   305R—opening for the shunt shaft and worm 402 in gear box half 305-   305W—seat for bearing 412 which supports third magnet rotor assembly    992-   306—first end gear box-   306A—wheel well-   306B—semi-cylindrical shunt gear housing in the first end gear box    half 306-   306C—semi-cylindrical drive gear housing in the first end gear box    half 306-   306D—bearing mount/well in gear box 306-   306F—bearing seat-   306K—upper shoulder in the gear box limiting the shunt worm's upper    movement-   306L—bearing seat, upper bearing, shunt worm-   306M—upper shoulder in the gear box limiting the drive worm's upper    movement-   306N—bearing seat, upper bearing, drive worm-   305S—bearing support for propulsion shaft bearing 560-   306R—opening for the propulsion shaft and worm 558 in gear box half    306-   306X—bearing seat in first end gear box half, 306, and opening for    the rotor shaft end 515-   306Y—shoulder in gear box half 306 which limits movement of the    shunt worm wheel 614-   306Z—shoulder in gear box half 306 which limits movement of the    drive worm wheel 608-   307—second end gear box half-   307A—wheel well-   307X—bearing seat for bearing 407 in second end gear box half, 307-   308—second end gear box side plate-   308A—wheel well-   308X—bearing seat for bearing 547 in second end gear box half 308-   309—first end gear box bottom plate-   309A—opening in first end gear box bottom plate which houses shunt    shaft worm 402-   309B—opening in first end gear box bottom plate which houses drive    shaft worm 558-   309C—cylindrical wall in base plate 309-   309G—lip in base plate 309-   309H—shoulder-   309S—shoulder supporting lower bearing 609A for shunt worm wheel 614    which drives vertical shunt worm wheel 612-   309K, 309L—bearing support in end plate-   309W—cylindrical wall in base plate 309-   310—second end gear box bottom plate-   311—base plate-   311A—first end of base plate 311-   311B—second end of base plate 311-   312—rotor-   313—rotor-   320—flat interior face of second backing bar weldment-   321—pin mounting-   322—recess in second backing bar weldment-   323—flat surface of second backing bar weldment-   324—wall of wire slot-   326—housing in second backing bar weldment for rotatable magnets-   326C—circular opening in end surface 326E-   326E—end surface in housing 326 in second backing bar weldment-   327—housing in second backing bar weldment for rotatable magnets-   328—slot in second backing bar weldment-   329—recess in second backing bar weldment for motor housing of    propulsion motor-   330—recess in second backing bar weldment for motor housing of    magnet motor-   331—passageway for propulsion drive shaft-   340—access port for adjustment of threaded stud 402N for adjustment    of thrust bearing 402B of magnet shaft-   340S—guide groove in first end gear box half 305 which receives    guide pin 415S-   341—access port for adjustment of threaded stud 403N for adjustment    of thrust bearing 403B of magnet shaft-   341S—guide groove in second end gear box half 307 which receives    guide pin 418S-   389, 305H—bearing shoulder-   399G—lip in base plate 309-   399S—shoulder supporting lower bearing 609 for drive worm wheel 608    which drives vertical shunt worm 605-   400—cross-sectional view taken along the line 4-4 of FIG. 3A-   400A—cross-sectional view taken along the line 4-4 of FIG. 3A-   401—magnet drive shaft-   401F, 401S—end of magnet drive shaft-   402—first end magnet drive shaft worm-   402B—thurst bearing of magnet drive shaft 401-   402C—partial cylinder-   402G—grip of threaded stud 402N-   402K—cylindrical portion of partial cylinder-   402N—threaded stud 402N for adjustment of thrust bearing 402B-   402R—bore in partial cylinder 402C-   402S—shoulder on magnet drive shaft limiting movement of worm 402-   402T—threads in adjustment bore 402R-   402Z—flat portion of partial cylinder 402C providing room for worm    wheel 608-   403—second end magnet drive shaft worm-   403B—thrust bearing of magnet shaft 401-   403C—partial cylinder-   403G—grip of threaded stud 403N-   403N—threaded stud 402N for adjustment of thrust bearing 402B-   403P—pin locking rotation of first end magnet drive shaft worm 403    with magnet drive shaft 401-   403R—bore in partial cylinder 403C-   403S—shoulder on magnet drive shaft limiting movement of worm 403-   403T—threaded hole-   404—spur gear and set screw affixed to magnet drive shaft 401-   405—motor shunt support-   406—bearing supporting second end shaft worm 403 and magnet drive    shaft 401-   407—bearing supporting fourth magnet rotor assembly 994-   408—fourth helical gear driving fourth magnet rotor assembly 994-   410—rotor shaft end of fourth magnet rotor assembly 994 distally    located with respect to second end gear drive system-   410D—circular opening in cylindrical housing 426 in backing bar    weldment 301-   410S—snap ring securing rotor shaft end of fourth magnet rotor    assembly 994-   411—rotor shaft end of third magnet rotor assembly 992 distally    located with respect to second end gear drive system-   411D—circular opening in cylindrical housing 427 in backing bar    weldment 301-   412—bearing supporting third magnet rotor assembly 992-   413—third rotor shaft end of third magnet rotor assembly 992-   414—third helical gear driving third magnet rotor assembly 992-   415—pin locking rotation of first end magnet drive shaft worm 402    with magnet drive shaft 401-   415S—pin preventing rotation of partial cylinder 402C-   416—bearing supporting first end shaft worm 402 and magnet drive    shaft 401-   416S—snap-ring securing bearing 416-   417S—snap-ring securing bearing 416-   418S—pin preventing rotation of partial cylinder 403C-   419C—cupped surface on end of threaded stud 402N for adjustment of    thrust bearing 402B-   420C—cupped surface on end of threaded stud 403N for adjustment of    thrust bearing 403B-   421, 422, 423, 424—magnets of third magnet rotor assembly 992-   421B—bottom portion of third magnet rotor assembly 992-   421N, 422N, 423N, 424N—north pole of magnets in third magnet rotor    assembly 992-   421P, 422P, 423P, 424P—pins securing magnets in third magnet rotor    assembly 992-   421S, 422S, 423S, 424S—south pole of magnets in third magnet rotor    assembly 992-   421T—top portion of third magnet rotor assembly 992-   426, 427—cylindrical housing in first backing bar weldment 301-   434T—top portion of fourth magnet rotor assembly 994-   434B—bottom portion of fourth magnet rotor assembly 994-   434, 435, 436, 437—magnets of fourth magnet rotor assembly 994-   434, 435H, 436H, 437H—holes in magnets-   434L—lower lip of bottom portion 434B of third magnet rotor assembly    992 in which rotor shaft end fits-   434N, 435N, 436N, 436N—north pole of magnets in fourth rotor    assembly 994-   434P, 435P, 436P, 437P—pins securing magnets in fourth magnet rotor    assembly 994-   434S, 435S, 436S, 437S—south pole of magnets in fourth magnet rotor    assembly 994-   434U—upper lip of top portion 434T of fourth magnet rotor assembly    994-   438—snap-ring securing spur gear 404 axially on magnet drive shaft-   438S—set screw for spur gear 404-   434T—top portion of fourth magnet rotor assembly 994-   439—snap ring securing bearing 406-   450—lines of magnetic field between magnets 421, 422, 423, 424 and    434, 435, 436, 437-   453S—snap ring securing bearing 406-   470—rotor shaft end for fourth magnet rotor assembly 994-   471—retaining slot for magnet 437-   471C—semi-circumferential lip engaging rotor shaft end 470-   472—retaining slot for magnet 437-   473—circumferentially shaped lip of rotor shaft end 470-   474—shaft portion of rotor shaft end 470-   475—locking flat portion of shaft portion 474-   476—locking flat portion of fourth helical gear 408-   481, 482, 483, 484—hole for pins through top portion 434T and bottom    portion 434B of rotor magnet assembly 994-   491—rotor shaft distal end of magnet rotor assembly 993-   491S—snap-ring restraining rotor shaft end 491-   499—pipe or conduit under inspection-   500—cross-sectional view taken along the lines 5-5 of FIG. 3A-   500A—cross-sectional view taken along the lines 5-5 of FIG. 3A with    a pipe in the view-   500B—cross-sectional view taken along the lines 5-5 of FIG. 3A with    rotor assemblies 991, 991 rotated 90°-   514—first helical rotor shaft gear driving rotor assembly 991-   515—first end rotor shaft end proximate gear drive system of rotor    assembly 991-   516—bearing supporting rotor assembly 991-   525, 526, 527, 528—magnets in magnet rotor assembly 991-   525B—bottom of magnet rotor assembly 991-   525N, 526N, 527N, 528N—north pole of magnets in magnet rotor    assembly 991-   525S, 526S, 527S, 528S—south pole of magnets in magnet rotor    assembly 991-   525P, 526P, 527P, 528P—pins securing magnets in magnet rotor    assembly 991-   525T—top of magnet rotor assembly 991-   530, 531, 532, 533—magnets in second magnet rotor assembly 993-   530B—bottom of second magnet rotor assembly 993-   530H, 531H, 532H, 533H—holes in magnets-   530L—lower lip of bottom portion 530B of second magnet rotor    assembly 993 in which rotor shaft end fits-   530N, 531N, 532N, 533N—north pole of magnets in second magnet rotor    assembly 993-   530P, 531P, 532P, 533P—pins securing magnets in second magnet rotor    assembly 993-   530S, 531S, 532S, 533S—south pole of magnets in second magnet rotor    assembly 993-   530T—top of second magnet rotor assembly 993-   530U—upper lip of top portion 530T of fourth magnet rotor assembly    994-   547—bearing supporting second magnet rotor assembly 993-   548—second helical gear driving fourth magnet rotor assembly 994-   549—rotor shaft end of second magnet rotor assembly 993 residing at    the second end of the device-   550—propulsion drive shaft-   551—second end propulsion drive shaft worm-   552—pin locking rotation of second end propulsion shaft worm 551    with propulsion drive shaft 550-   552S—slot in second end propulsion drive shaft worm 551-   553—bearing supporting second end shaft worm 551 and propulsion    drive shaft 550-   553S, 554S—snap ring securing bearing 553 to propulsion drive shaft    550-   555—spur gear driven by gear 620 driven by propulsion motor-   556S, 561S—snap-rings securing bearing 560-   557—pin locking rotation of first end prolusion shaft worm 558 with    propulsion drive shaft 550-   557S—slot in first end prolusion drive shaft worm 558-   558—first end propulsion drive shaft worm-   559—snap ring securing first end propulsion drive shaft worm 558-   560—bearing supporting first end shaft worm 558 and propulsion drive    shaft 550-   562S—snap-ring securing spur gear 555 on propulsion drive shaft 550-   570S—snap ring securing second end propulsion drive shaft worm 551-   571—retaining slot for magnet 533-   571C—semi-circumferential lip engaging rotor shaft end 549-   572—retaining slot for magnet 533-   573—circumferentially shaped lip of rotor shaft end 549-   574—shaft portion of rotor shaft end 570-   576—locking flat portion of second helical gear 548-   575—locking flat of shaft 574 of magnet rotor assembly-   581, 582, 583, 584—hole for pins through top portion 530T and bottom    portion 530B of rotor assembly 993-   587—shunt motor spur gear-   590—rotor shaft end of rotor assembly 991 distally located with    respect to first end gear drive system-   590D—circular opening in cylindrical housing 326 in backing bar    weldment 302-   591—rotor shaft end of rotor assembly 993 distally located with    respect to second end gear drive system-   591D—circular opening in cylindrical housing 327 in backing bar    weldment 302-   597—set screw for spur gear 555-   600—cross-sectional view taken along the line 6-6 of FIG. 3A-   600A—enlargement of a portion of FIG. 6-   600B—enlargement of a portion of FIG. 6A-   601—gearbox which includes halves 305, 306-   602—gearbox which includes halves 307, 308-   603—upper bearing supporting drive shaft 604-   604—drive shaft for drive worm wheel 608 and vertical drive worm 605    which rotates wheel drive gear 680-   605—vertical drive worm for rotating wheel drive gear 680-   606—pin securing drive worm wheel 608 to drive shaft 604-   607—pin slot in drive shaft 604-   608—drive worm wheel engaging drive shaft worm 558-   609—bearing supporting drive worm wheel 608-   609A—bearing supporting shunt worm wheel 614-   610—upper bearing supporting drive shaft 611-   611—drive shaft for vertical shunt worm wheel 612 which rotates    magnet rotor assemblies 991, 992-   612—vertical shunt worm which rotates magnet rotor assemblies 991,    992-   613—pin securing shunt worm wheel 614 to drive shaft 611-   614—shunt worm wheel engaging shunt shaft worm 402-   615—spacer between bearing 609A and shunt worm wheel 614-   615A—spacer between vertical shunt worm wheel 612 and upper bearing    610-   616—propulsion motor support-   617—spacer between bearing 609 and drive worm wheel 608-   617A—spacer between vertical shunt worm 605 and upper bearing 603-   620—motor driven spur gear-   620A—propulsion motor-   621—motor support-   622—motor shaft bearing-   630—shunt motor support-   631—shunt motor driven gear-   632—shunt motor shaft bearing-   633—bearing supporting shunt worm wheel 635-   634—spacer between bearing 633 and shunt worm wheel 635-   634A—spacer between bearing 637 and vertical worm shunt worm 636-   635—shunt worm wheel engaging shunt shaft worm 403-   636—vertical shunt worm for rotating the magnet rotor assemblies    993, 994-   637—upper bearing supporting drive shaft 638-   638—drive shaft for vertical shunt worm wheel 635 which rotates    magnet rotor assemblies 993. 994-   639—drive shaft for drive worm wheel 644 and vertical drive worm 643    which rotates wheel drive gear 682-   640—upper bearing supporting drive shaft 639-   641—pin securing shunt worm wheel 635 to drive shaft 638-   642—pin securing shunt worm wheel 644 to drive shaft 639-   643—vertical drive worm for rotating wheel drive gear 682-   644—drive worm wheel engaging drive shaft worm 551-   645—spacer between bearing 646 and drive worm wheel 644-   645A—spacer between bearing 640 and drive worm 643-   646—bearing supporting drive worm wheel 644-   680, 682—propulsion wheel drive gear-   680F, 682F—integral collar for affixation of drive gear to    propulsion wheel drive shaft-   681, 683—propulsion wheel drive shaft-   681S, 681H—bearing restraining shoulders on shaft 681-   698—shunt motor-   698S—shunt motor shaft-   699—bolt hole-   700—plan view of magnet drive shaft 401, first end worm 402, spur    gear 404 affixed to shaft 401 and second end worm 403-   700A—cross-sectional view taken along the lines 7A-7A of FIG. 7-   700B—enlargement of the first end portion of FIG. 7-   700C—cross-sectional enlargement of the first end portion of FIG. 7-   700D—enlargement of the second end portion of FIG. 7-   700E—cross-sectional enlargement of the second end portion of FIG. 7-   700F—is a top view of partial cylinder which provides thrust bearing    support for the magnet drive shaft.-   700G—is an end view of the partial cylinder which provides thrust    bearing support for the magnet drive shaft.-   800—plan view of magnet drive shaft 550, first end worm 558, spur    gear 555 affixed to shaft 550 and second end worm 551-   800A—cross-sectional view taken along the lines 8A-8A of FIG. 8-   800B—enlargement of the first end portion of FIG. 8-   800C—cross-sectional enlargement of the first end portion of FIG. 8-   800D—enlargement of the second end portion of FIG. 8-   800E—cross-sectional enlargement of the second end portion of FIG. 8-   805A—propulsion motor-   900—top view of the conduit sensor with magnetic shunt with the    backing bar weldments and the gear boxes removed-   900A—bottom view of the first end of FIG. 9-   900B—bottom view of the second end of FIG. 9-   900C—perspective view of the first end of FIG. 9-   900D—perspective view of the second end of FIG. 9-   900E—exploded perspective view of fourth magnet rotor assembly 994-   900F—exploded perspective view of magnet rotor assemblies 993 and    994-   900G—a schematic perspective view of FIG. 9C indicating rotation of    the shunt drive shaft in the clockwise direction as defined from the    perspective of the first end of the conduit sensor device and also    indicating rotation of the propulsion drive shaft in the clockwise    directions as defined from the perspective of the first end of the    conduit sensor device-   900H—a schematic perspective view of FIG. 9C indicating rotation of    the shunt drive shaft in the counter clockwise direction as defined    from the perspective of the first end of the conduit sensor device    and also indicating rotation of the propulsion drive shaft in the    counter clockwise directions as defined from the perspective of the    first end of the conduit sensor device-   900I—a schematic perspective view of FIG. 9D indicating rotation of    the shunt drive shaft in the clockwise direction as defined from the    perspective of the first end of the conduit sensor device and also    indicating rotation of the propulsion drive shaft in the clockwise    directions as defined from the perspective of the first end of the    conduit sensor device-   900J—a schematic perspective view of FIG. 9D indicating rotation of    the shunt drive shaft in the counter clockwise direction as defined    from the perspective of the first end of the conduit sensor device    and also indicating rotation of the propulsion drive shaft in the    counter clockwise directions as defined from the perspective of the    first end of the conduit sensor device.-   901, 902, 903, 904—wheel bearings-   905—propulsion output spur gear-   905—spur gear driven by propulsion motor 905A-   950—arrow indicating clockwise direction of shaft 401 viewed from    first end-   951—arrow indicating clockwise direction of shaft 550 viewed from    first end-   952—arrow indicating clockwise direction of worm wheel 614 viewed    from above first end-   952A—arrow indicating clockwise direction of vertical worm 612    viewed from above first end-   953—arrow indicating clockwise rotation of first helical gear 514    coupled to magnet rotor assembly 991-   954—arrow indicating counter clockwise rotation of third helical    gear 414 coupled to third magnet rotor assembly 992-   955—arrow indicating the direction of travel of helical gear teeth    of helical gears 514, 414 with respect to vertical worm 612-   956—arrow indicating the counter clockwise rotation of worm wheel    608-   957—arrow indicating the counter clockwise rotation of vertical worm    605-   958—arrow indicating the counter clockwise rotation of the worm    wheel gear 680 as viewed in FIG. 9G-   959—arrow indicating the direction of travel of the helical gear    teeth of worm wheel 614-   960—arrow indicating the direction of travel of the helical gear    teeth of worm wheel 608-   961—arrow indicating the counter clockwise rotation of helical wheel    gear 644-   962—arrow indicating the counter clockwise rotation of left handed    vertical worm 643-   963—arrow indicating the counter clockwise rotation of worm wheel    gear 682 viewed in FIG. 9I-   964—arrow indicating the direction of travel of the worm wheel 644    with respect to worm 551-   965—arrow indicating the clockwise direction of worm wheel 635-   965A—arrow indicating the clockwise direction of vertical worm 636-   966—arrow indicating clockwise rotation of fourth helical gear 408-   967—arrow indicating counter clockwise rotation of second helical    gear 548-   968—arrow indication the direction of travel of worm 635 with    respect to shunt shaft mounted worm 403-   969—arrow indicating the direction of travel of helical gears 408,    548 with respect to vertical worm 636-   970—arrow indicating the counter clockwise rotation of worm 402 and    shunt shaft 401-   971—arrow indicating the counter clockwise rotation of worm 558 and    propulsion shaft 550-   972—arrow indicating the counter clockwise rotation of worm wheel    614-   972A—arrow indicating the counter clockwise rotation of worm 612-   973—arrow indicating counter clockwise rotation of first helical    gear 514-   974—arrow indicating the clockwise rotation of third helical gear    414-   975—arrow indicating the counter clockwise rotation of helical gear    635-   975A—arrow indicating counter clockwise rotation of worm 636-   976—arrow indicating the counter clockwise rotation of fourth    helical gear 408-   978—arrow indicating the clockwise rotation of second helical gear    548-   979—arrow indicating the direction of travel of worm wheel 635 with    respect to worm 403-   980—arrow indicating the direction of travel of worm wheel 644 with    respect to worm 551-   981—arrow indicating clockwise rotation of worm wheel 644-   982—arrow indicating clockwise rotation of worm 643-   983—arrow indicating the rotational of worm wheel 682-   984—arrow indicating the direction of travel of worm wheel 682 with    respect to worm 643-   984A—arrow indicating the direction of travel of helical gears 408,    548 with respect to worm 636-   985—arrow indicating clockwise rotation of wheel worm 608-   986—arrow indicating direction of travel of worm wheel 608 with    respect to worm 558-   987—arrow indicating clockwise rotation of vertical worm 605-   987A—arrow indicating direction of travel of teeth of worm wheel 680    with respect to vertical worm 605-   988—arrow indicating clockwise rotation of worm wheel 680-   991—first magnet rotor assembly residing at first end-   992—third magnet rotor assembly residing at first end of the device-   993—second magnet rotor assembly residing at second end of the    device-   994—fourth magnet rotor assembly residing at second end-   1000—cross-sectional view taken along the lines 10-10 of FIG. 3-   1000A—cross-sectional view taken along the lines 10-10 of FIG. 3    with the rotor assemblies 993, 994 rotated 90°-   1001, 1002, 1003, 1004—magnetic field lines in the shunted/cancelled    position of FIG. 10A-   1010—rear or rearward portion of the conduit sensor device-   1011—front or forward portion of the conduit sensor device-   1012—central portion of the conduit sensor device-   1100—cross-sectional view taken along the lines 11-11 of FIG. 3-   1101, 1102, 1103, 1104—magnetic field lines in the shunted/cancelled    position of FIG. 11A-   1100A—cross-sectional view taken along the lines 11-11 of FIG. 3    with the rotor assemblies 991, 992 rotated 90°

The invention has been disclosed by way of example. Those skilled in theart will readily recognize that changes and modifications may be made tothe invention without departing from the spirit and the scope of theappended claims.

1. A conduit sensor device, comprising: a first end of said device; a second end of said device; a first gearbox residing at said first end of said device; a second gearbox residing at said second end of said device; a propulsion shaft, said propulsion shaft includes a first end and a second end; a propulsion shaft extending from said first end of said device to a second end of said device, said propulsion shaft rotatable in clockwise and counter clockwise directions when viewed from said first end of said device; a first worm affixed to said first end of said propulsion shaft and a second worm affixed to said second end of said propulsion shaft; said first gearbox includes: a first wheel worm driven by said first worm of said propulsion shaft; a first vertical worm affixed to said first wheel worm; a first drive wheel worm, said first vertical worm engaging said first drive wheel worm and rotating same in response to the direction of said propulsion shaft; said second gearbox includes: a second wheel worm driven by said second worm of said propulsion shaft; a second vertical worm affixed to said second wheel worm: a second drive wheel worm, said second vertical worm engaging said second drive wheel worm and rotating same in the direction of said first drive wheel worm.
 2. A conduit sensor device as claimed in claim 1 wherein said second vertical worm and said second wheel worm are left-handed.
 3. A conduit sensor device as claimed in claim 1 wherein if said propulsion shaft is rotated clockwise when viewed from said first end, then said first drive wheel worm and said second drive wheel worm propel said device rightwardly.
 4. A conduit sensor device as claimed in claim 1 wherein if said propulsion shaft is rotated counter clockwise when viewed from said first end, then said first drive wheel worm and said second drive wheel worm propel said device leftwardly.
 5. A conduit sensor device as claimed in claim 1 wherein first drive wheel worm and said second drive wheel worm rotate synchronously and wherein a first wheel is affixed to said first drive wheel worm and a second wheel is affixed to said second drive wheel worm.
 6. A method of operating a conduit sensor device, comprising the steps of: rotating a propulsion shaft having first and second worms affixed thereto and rotating therewith; rotating, using said first worm, a first worm wheel and a first vertical worm affixed thereto; rotating, using said first vertical worm, a first drive wheel worm having a first drive wheel affixed thereto; rotating, using said second worm, a second drive worm wheel and a second vertical worm affixed thereto; and, rotating, using said second vertical worm, a second drive worm wheel having a second drive wheel affixed thereto.
 7. A method of operating a conduit sensor device as claimed in claim 6, further comprising the steps of: synchronizing said first and second drive wheels. 